11242 + Mcqs in Chemistry Page 139 McqOptions

6901.	The number of electrons that are paired in oxygen molecule is [IIT 1995]
A.	7
B.	8
C.	14
D.	16
Answer» D. 16

Discussion

6902.	Which of the given sets of temperature and pressure will cause a gas to exhibit the greatest deviation from ideal gas behavior [DCE 2003]
A.	\[{{100}^{o}}C\] and 4 atm
B.	\[{{100}^{o}}C\] and 2 atm
C.	\[-{{100}^{o}}C\] and 4 atm
D.	\[{{0}^{o}}C\] and 2 atm
Answer» D. \[{{0}^{o}}C\] and 2 atm

Discussion

6903.	Kp for the following reaction at 700 K is \[1.3\times {{10}^{-3}}\] atm-1. The Kc at same temperature for the reaction \[2S{{O}_{2}}+{{O}_{2}}\] \[2S{{O}_{3}}\] will be [AIIMS 2001]
A.	\[1.1\ \times \ {{10}^{-2}}\]
B.	\[3.1\ \times \ {{10}^{-2}}\]
C.	\[5.2\ \times \ {{10}^{-2}}\]
D.	\[7.4\ \times \ {{10}^{-2}}\]
Answer» E.

Discussion

6904.	Which one of the following compound is not a protonic acid [CBSE PMT 2003]
A.	\[S{{O}_{2}}{{(OH)}_{2}}\]
B.	\[B{{(OH)}_{3}}\]
C.	\[PO{{(OH)}_{3}}\]
D.	\[SO{{(OH)}_{2}}\]
Answer» C. \[PO{{(OH)}_{3}}\]

Discussion

6905.	\[{{H}_{2}}S\] acts only as a reducing agent while \[S{{O}_{2}}\]can act both as a reducing and oxidizing agent because [AMU 1999]
A.	\[S\]in \[{{H}_{2}}S\]has - 2 oxidation state
B.	\[S\]in \[S{{O}_{2}}\]has oxidation state + 4
C.	Hydrogen in \[{{H}_{2}}S\]more +ve than oxygen
D.	Oxygen is more - ve in \[S{{O}_{2}}\]
Answer» B. \[S\]in \[S{{O}_{2}}\]has oxidation state + 4

Discussion

6906.	Which of the following oxide is diamagnetic [MP PET 1990]
A.	\[NO\]
B.	\[N{{H}_{3}}\]
C.	\[{{N}_{2}}{{H}_{4}}\]
D.	\[{{N}_{2}}{{H}_{2}}\]
Answer» C. \[{{N}_{2}}{{H}_{4}}\]

Discussion

6907.	Identify the species X in the reaction : \[\text{Propene }+O\text{ (conc}\text{. acidic }KMn{{O}_{4}})\to X+\text{Formic acid}\]
A.	Acetone
B.	Acetaldehyde
C.	Isopropanol
D.	Acetic acid
Answer» E.

Discussion

6908.	Which can be described as a molecule with residual bonding capacity [JIPMER 2000]
A.	\[BeC{{l}_{2}}\]
B.	\[NaCl\]
C.	\[C{{H}_{4}}\]
D.	\[{{N}_{2}}\]
Answer» B. \[NaCl\]

Discussion

6909.	The solubility product of Mg\[{{(OH)}_{2}}\]is\[1.2\times {{10}^{-11}}\]. The solubility of this compound in gram per \[100\,c{{m}^{3}}\] of solution is [Roorkee 2000]
A.	\[1.4\times {{10}^{-4}}\]
B.	\[8.16\times {{10}^{-4}}\]
C.	0.816
D.	1.4
Answer» C. 0.816

Discussion

6910.	Philospher's wool when heated with \[BaO\] at \[{{1100}^{o}}C\] gives a compound. Identify the compound [CPMT 1997]
A.	\[BaZn{{O}_{2}}\]
B.	\[Ba+Zn{{O}_{2}}\]
C.	\[BaCd{{O}_{2}}\]
D.	\[Ba{{O}_{2}}+Zn\]
Answer» B. \[Ba+Zn{{O}_{2}}\]

Discussion

6911.	The ionization of hydrogen atom would give rise to [UPSEAT 2001]
A.	Hybrid ion
B.	Hydronium ion
C.	Proton
D.	Hydroxyl ion
Answer» D. Hydroxyl ion

Discussion

6912.	Which of the following is Lewis acid [Pb. CET 2000]
A.	S
B.	\[:C{{H}_{2}}\]
C.	\[{{(C{{H}_{3}})}_{3}}B\]
D.	All of these
Answer» E.

Discussion

6913.	Magnesium burns in air to give [CPMT 1988, 89; AFMC 1987]
A.	\[MgO\]
B.	\[M{{g}_{3}}{{N}_{2}}\]
C.	\[MgC{{O}_{3}}\]
D.	\[MgO\] and \[M{{g}_{3}}{{N}_{2}}\] both
Answer» E.

Discussion

6914.	Number of structural isomers of \[{{C}_{4}}{{H}_{10}}O\] are [CPMT 1983, 84, 89, 91; MADT Bihar 1984; MNR 1984; MP PET 1997; Pb. PMT 1999; MH CET 2003]
A.	3
B.	6
C.	7
D.	10
Answer» D. 10

Discussion

6915.	What is formed when calcium carbide react with heavy water [CPMT 1999]
A.	\[{{C}_{2}}{{D}_{2}}\]
B.	\[Ca{{D}_{2}}\]
C.	\[Ca{{D}_{2}}O\]
D.	\[C{{D}_{2}}\]
Answer» B. \[Ca{{D}_{2}}\]

Discussion

6916.	Bonds present in \[CuS{{O}_{4}}.5{{H}_{2}}O\]is [IIT 1983; DCE 2001]
A.	Electrovalent and covalent
B.	Electrovalent and coordinate
C.	Electrovalent, covalent and coordinate
D.	Covalent and coordinate
Answer» D. Covalent and coordinate

Discussion

6917.	Which one is the strongest acid [MH CET 1999; AMU 1999,2000; Pb.CET 2001,03; MP PET 2001]
A.	\[HClO\]
B.	\[HCl{{O}_{2}}\]
C.	\[{{H}_{2}}S{{O}_{4}}\]
D.	\[HCl{{O}_{4}}\]
Answer» E.

Discussion

6918.	The solubility in water of sulphates down the \[Be\] group is \[Be>Mg>>Ca>Sr>Ba\]. This is due to [CBSE PMT 1995]
A.	High heat of solvation for smaller ions like \[B{{e}^{2+}}\]
B.	Increasing molecular weight
C.	Decreasing lattice energy
D.	Increase in melting points
Answer» B. Increasing molecular weight

Discussion

6919.	The compound X on reaction with \[HgS{{O}_{4}}+{{H}_{2}}S{{O}_{4}}\] gives Y which on oxidation gives acetic acid. X is [MP PMT 1999]
A.	\[{{C}_{2}}{{H}_{2}}\]
B.	\[{{C}_{2}}{{H}_{4}}\]
C.	\[{{C}_{3}}{{H}_{4}}\]
D.	\[{{C}_{4}}{{H}_{6}}\]
Answer» B. \[{{C}_{2}}{{H}_{4}}\]

Discussion

6920.	A compound contains atoms \[X,\,\,Y,\,\,Z.\] The oxidation number of \[X\]is \[sp-s{{p}^{2}}\] is + 5 and \[Z\] is \[-\,2\]. Therefore, a possible formula of the compound is [CPMT 1988]
A.	\[XY{{Z}_{2}}\]
B.	\[{{X}_{2}}\,{{\left( Y{{Z}_{3}} \right)}_{2}}\]
C.	\[{{X}_{3}}\,{{\left( Y{{Z}_{4}} \right)}_{2}}\]
D.	\[{{X}_{3}}\,{{\left( {{Y}_{4}}Z \right)}_{2}}\]
Answer» D. \[{{X}_{3}}\,{{\left( {{Y}_{4}}Z \right)}_{2}}\]

Discussion

6921.	The \[pH\] of 0.1 M solution of a weak monoprotic acid 1% ionized is [UPSEAT 2001; Pb. PMT 2001]
A.	1
B.	2
C.	3
D.	4
Answer» D. 4

Discussion

6922.	The atomic number of vanadium (V), chromium (Cr), manganese (Mn) and iron (Fe) are respectively 23, 24, 25 and 26 which one of these may be expected to have the highest second ionization enthalpy [AIEEE 2003]
A.	V
B.	Cr
C.	Mn
D.	Fe
Answer» C. Mn

Discussion

6923.	In a reaction of \[{{C}_{6}}{{H}_{5}}Y,\] the major product (> 60%) is m-isomer, so the group Y is [AIIMS 1997; UPSEAT 2003]
A.	\[-COOH\]
B.	\[-N{{H}_{2}}\]
C.	\[-OH\]
D.	\[-Cl\]
Answer» B. \[-N{{H}_{2}}\]

Discussion

6924.	\[Ca{{C}_{2}}+{{H}_{2}}O\to A\xrightarrow{{{H}_{2}}S{{O}_{4}}/HgS{{O}_{4}}}B\]. Identify A and B in the given reaction [CPMT 2000; BVP 2004]
A.	\[{{C}_{2}}{{H}_{2}}\]and \[C{{H}_{3}}CHO\]
B.	\[C{{H}_{4}}\]and \[HCOOH\]
C.	\[{{C}_{2}}{{H}_{4}}\]and\[C{{H}_{3}}COOH\]
D.	\[{{C}_{2}}{{H}_{2}}\]and \[C{{H}_{3}}COOH\]
Answer» B. \[C{{H}_{4}}\]and \[HCOOH\]

Discussion

6925.	Strongest intermolecular hydrogen bond is present in the following molecules pairs [IIT 1981; DCE 2000]
A.	\[Si{{H}_{4}}\] and \[SiF\]
B.	\[C{{H}_{3}}-\overset{\overset{O}{\mathop{\|\|}}\,}{\mathop{C}}\,-C{{H}_{3}}\] and \[CHC{{l}_{3}}\]
C.	\[H-\overset{\overset{O}{\mathop{\|\|}}\,}{\mathop{C}}\,-OH\] and \[C{{H}_{3}}-\overset{\overset{O}{\mathop{\|\|}}\,}{\mathop{C}}\,-OH\]
D.	\[{{H}_{2}}O\] and \[{{H}_{2}}{{O}_{2}}\]
Answer» D. \[{{H}_{2}}O\] and \[{{H}_{2}}{{O}_{2}}\]

Discussion

6926.	The degree of hydrolysis of a salt of weak acid and weak base in its 0.1 M solution is found to be 50%. If the molarity of the solution is 0.2 M, the percentage hydrolysis of the salt should be [AMU 1999]
A.	50%
B.	35%
C.	75%
D.	100%
Answer» B. 35%

Discussion

6927.	Which of the following is the most stable cation [CBSE PMT 1988; MNR 1988; AIIMS 1985]
A.	\[C{{H}_{3}}C{{H}_{2}}\overset{+}{\mathop{C}}\,HC{{H}_{3}}\]
B.	\[C{{H}_{3}}-\underset{C{{H}_{3}}\,\,\,\,}{\mathop{\underset{\|\,\,\,\,\,\,\,\,\,\,\,}{\mathop{\overset{+}{\mathop{C}}\,C{{H}_{3}}}}\,}}\,\]
C.	\[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}\overset{+}{\mathop{C}}\,{{H}_{2}}\]
D.	\[CH_{3}^{+}\]
Answer» C. \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}\overset{+}{\mathop{C}}\,{{H}_{2}}\]

Discussion

6928.	Toluene can be oxidised to benzoic acid by [AIIMS 1999]
A.	\[KMN{{O}_{4}}\]
B.	\[{{K}_{2}}C{{r}_{2}}{{O}_{7}}\]
C.	\[{{H}_{2}}S{{O}_{4}}\]
D.	Both A and B
Answer» C. \[{{H}_{2}}S{{O}_{4}}\]

Discussion

6929.	As electron moves away from the nucleus, its potential energy [UPSEAT 2003]
A.	Increases
B.	Decreases
C.	Remains constant
D.	None of these
Answer» B. Decreases

Discussion

6930.	The number of \[SS\] bonds in sulphur trioxide trimer \[{{S}_{3}}O{}_{9}\] is [IIT Screening 2001]
A.	Three
B.	Two
C.	One
D.	Zero
Answer» E.

Discussion

6931.	A precipitate of \[Ca{{F}_{2}}\,\,({{K}_{sp}}=1.7\times {{10}^{-10}})\] will be obtained when equal volume of the following are mixed [MP PMT 1990, 95; IIT 1982; MNR 1992]
A.	\[{{10}^{-4}}M\,C{{a}^{2+}}\] and \[{{10}^{-4}}M\,{{F}^{-}}\]
B.	\[{{10}^{-2}}M\,C{{a}^{2+}}\] and \[{{10}^{-3}}M\,{{F}^{-}}\]
C.	\[{{10}^{-5}}M\,C{{a}^{2+}}\] and \[{{10}^{-4}}M\,{{F}^{-}}\]
D.	\[{{10}^{-3}}M\,C{{a}^{2+}}\] and \[{{10}^{-4}}M\,{{F}^{-}}\]
Answer» C. \[{{10}^{-5}}M\,C{{a}^{2+}}\] and \[{{10}^{-4}}M\,{{F}^{-}}\]

Discussion

6932.	Six volumes of oxygen, on complete ozonisation, form ...... volumes of ozone [DPMT 2000]
A.	4
B.	3
C.	2
D.	6
Answer» B. 3

Discussion

6933.	Benzene is obtained by [DPMT 2002]
A.	Substitution of three acetylene molecules
B.	Addition of three \[{{C}_{2}}{{H}_{2}}\]molecules
C.	Polymerisation of three \[{{C}_{2}}{{H}_{2}}\] molecules
D.	Condensation of three \[{{C}_{2}}{{H}_{2}}\]molecules
Answer» D. Condensation of three \[{{C}_{2}}{{H}_{2}}\]molecules

Discussion

6934.	The value of Planck?s constant is \[6.63\times {{10}^{-34}}Js.\] The velocity of light is \[3.0\times {{10}^{8}}\,m{{s}^{-1}}\]. Which value is closest to the wavelength in nanometres of a quantum of light with frequency of \[8\times {{10}^{15}}{{s}^{-1}}\] [CBSE PMT 2003]
A.	\[3\times {{10}^{7}}\]
B.	\[2\times {{10}^{-25}}\]
C.	\[5\times {{10}^{-18}}\]
D.	\[4\times {{10}^{1}}\]
Answer» E.

Discussion

6935.	The common features among the species \[C{{N}^{-}}\], CO and \[N{{O}^{+}}\] are [IIT Screening 2001]
A.	Bond order three and isoelectronic
B.	Bond order three and weak field ligands
C.	Bond order two and p-acceptors
D.	Isoelectronic and weak field ligands
Answer» B. Bond order three and weak field ligands

Discussion

6936.	Which of the following oxides will not give \[O{{H}^{-}}\]in aqueous solution [NCERT 1980]
A.	\[F{{e}_{2}}{{O}_{3}}\]
B.	\[HI\]
C.	\[L{{i}_{2}}O\]
D.	\[{{K}_{2}}O\]
Answer» B. \[HI\]

Discussion

6937.	When \[Mn{{O}_{2}}\] is fused with KOH, a coloured compound is formed, the product and its colour is [IIT Screening 2003]
A.	\[{{K}_{2}}Mn{{O}_{4}}\], purple green
B.	\[KMn{{O}_{4}}\], purple
C.	\[M{{n}_{2}}{{O}_{3}}\], brown
D.	\[M{{n}_{3}}{{O}_{4}}\]black
Answer» B. \[KMn{{O}_{4}}\], purple

Discussion

6938.	In which block 106th element belongs [DCE 2000]
A.	s-block
B.	p-block
C.	d-block
D.	f-block
Answer» D. f-block

Discussion

6939.	Which order is correct for the decreasing reactivity to ring monobromination of the following compounds \[\begin{align} & {{C}_{6}}{{H}_{5}}C{{H}_{3}}, \\ & \,\,\,\,\,\,\,\,\,\,\text{I} \\ \end{align}\] \[\begin{align} & {{C}_{6}}{{H}_{5}}COOH, \\ & \,\,\,\,\,\,\,\,\,\,\,\,\,\text{II} \\ \end{align}\] \[\begin{align} & {{C}_{6}}{{H}_{6}} \\ & \,\,\,\,\text{III} \\ \end{align}\] \[\begin{align} & {{C}_{6}}{{H}_{5}}N{{O}_{2}} \\ & \,\,\,\,\,\,\,\,\,\,\text{IV} \\ \end{align}\]
A.	\[I>II>III>IV\]
B.	\[I>III>II>I\]
C.	\[II>III>IV>I\]
D.	\[III>I>II>IV\]
Answer» C. \[II>III>IV>I\]

Discussion

6940.	In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen [AIEEE 2003]
A.	3 ® 2
B.	5 ® 2
C.	4 ® 1
D.	2 ® 5
Answer» B. 5 ® 2

Discussion

6941.	\[{{N}_{2}}\] and \[{{O}_{2}}\] are converted into monocations \[N_{2}^{+}\] and \[O_{2}^{+}\] respectively. Which is wrong [CBSE PMT 1997]
A.	In \[{{N}_{2}},\] the \[N-N\]bond weakens
B.	In \[{{O}_{2}},\] the \[O-O\] bond order increases
C.	In \[{{O}_{2}},\] paramagnetism decreases
D.	\[N_{2}^{+}\] becomes diamagnetic
Answer» E.

Discussion

6942.	\[\Delta {{H}_{f}}\,({{H}_{2}}O)=X;\] Heat of neutralisation of \[C{{H}_{3}}COOH\]and \[NaOH\] will be [BHU 2003]
A.	Less than 2X
B.	Less than X
C.	X
D.	Between X and 2X
Answer» C. X

Discussion

6943.	The conductivity of a saturated solution of \[BaS{{O}_{4}}\] is \[3.06\times {{10}^{-6}}\,oh{{m}^{-1}}\,c{{m}^{-1}}\] and its equivalent conductance is \[1.53\,oh{{m}^{-1}}\,c{{m}^{-1}}\,equivalen{{t}^{-1}}\]. The \[{{K}_{sp}}\] of the \[BaS{{O}_{4}}\] will be [KCET 1996]
A.	\[4\,\times {{10}^{-12}}\]
B.	\[2.5\times {{10}^{-9}}\]
C.	\[2.5\times {{10}^{-13}}\]
D.	\[4\times {{10}^{-6}}\]
Answer» E.

Discussion

6944.	Calcium cyanide on treatment with steam under pressure gives \[N{{H}_{3}}\] and [DPMT 2002]
A.	\[CaHC{{O}_{3}}\]
B.	\[CaO\]
C.	\[Ca{{(OH)}_{2}}\]
D.	\[CaC{{O}_{3}}\]
Answer» E.

Discussion

6945.	The number of moles of \[KMn{{O}_{4}}\] that will be needed to react completely with one mole of ferrous oxalate \[Fe({{C}_{2}}{{O}_{4}})\] in acidic solution is [IIT-JEE 1997; KCET 1996]
A.	44319
B.	44318
C.	44320
D.	1
Answer» B. 44318

Discussion

6946.	The following reaction is described as [CBSE PMT 1997] \[\begin{matrix} C{{H}_{3}}{{(C{{H}_{2}})}_{5}} \\ {} \\ {{H}_{3}}C \\ \end{matrix}>\underset{H}{\mathop{\underset{\|}{\mathop{C}}\,}}\,-Br\xrightarrow{OH}HO-\underset{H}{\mathop{\underset{\|}{\mathop{C}}\,}}\,
A.	\[S{{E}^{2}}\]
B.	\[S{{N}^{1}}\]
C.	\[S{{N}^{2}}\]
D.	\[S{{N}^{0}}\]
Answer» D. \[S{{N}^{0}}\]

Discussion

6947.	A group which deactivates the benzene ring towards electrophilic substitution but which directs the incoming group principally to the o- and p-positions is [Pb. PMT 1998]
A.	\[-N{{H}_{2}}\]
B.	\[-Cl\]
C.	\[-N{{O}_{2}}\]
D.	\[-{{C}_{2}}{{H}_{5}}\]
Answer» C. \[-N{{O}_{2}}\]

Discussion

6948.	Which of the following electron transition in a hydrogen atom will require the largest amount of energy [UPSEAT 1999, 2000, 01]
A.	From \[n=1\] to \[n=2\]
B.	From \[n=2\] to \[n=3\]
C.	From \[n=\infty \] to \[n=1\]
D.	From \[n=3\] to \[n=5\]
Answer» B. From \[n=2\] to \[n=3\]

Discussion

6949.	Volume of the air that will be expelled from a vessel of 300 \[c{{m}^{3}}\] when it is heated from \[{{27}^{o}}C\] to \[{{37}^{o}}C\] at the same pressure will be
A.	310 \[c{{m}^{3}}\]
B.	290 \[c{{m}^{3}}\]
C.	10 \[c{{m}^{3}}\]
D.	37 \[c{{m}^{3}}\]
Answer» D. 37 \[c{{m}^{3}}\]

Discussion

6950.	Self-ionisation of liquid ammonia occurs as, \[2N{{H}_{3}}\]⇄\[NH_{4}^{+}+NH_{2}^{-};\,K={{10}^{-10}}\]. In this solvent, an acid might be [JIPMER 2001]
A.	\[NH_{4}^{+}\]
B.	\[N{{H}_{3}}\]
C.	Any species that will form \[NH_{4}^{+}\]
D.	All of these
Answer» B. \[N{{H}_{3}}\]

Discussion

Explore topic-wise MCQs in Joint Entrance Exam - Main (JEE Main).

The number of electrons that are paired in oxygen molecule is [IIT 1995]

Which of the given sets of temperature and pressure will cause a gas to exhibit the greatest deviation from ideal gas behavior [DCE 2003]

Kp for the following reaction at 700 K is \[1.3\times {{10}^{-3}}\] atm-1. The Kc at same temperature for the reaction \[2S{{O}_{2}}+{{O}_{2}}\] \[2S{{O}_{3}}\] will be [AIIMS 2001]

Which one of the following compound is not a protonic acid [CBSE PMT 2003]

\[{{H}_{2}}S\] acts only as a reducing agent while \[S{{O}_{2}}\]can act both as a reducing and oxidizing agent because [AMU 1999]

Which of the following oxide is diamagnetic [MP PET 1990]

Identify the species X in the reaction : \[\text{Propene }+O\text{ (conc}\text{. acidic }KMn{{O}_{4}})\to X+\text{Formic acid}\]

Which can be described as a molecule with residual bonding capacity [JIPMER 2000]

The solubility product of Mg\[{{(OH)}_{2}}\]is\[1.2\times {{10}^{-11}}\]. The solubility of this compound in gram per \[100\,c{{m}^{3}}\] of solution is [Roorkee 2000]

Philospher's wool when heated with \[BaO\] at \[{{1100}^{o}}C\] gives a compound. Identify the compound [CPMT 1997]

The ionization of hydrogen atom would give rise to [UPSEAT 2001]

Which of the following is Lewis acid [Pb. CET 2000]

Magnesium burns in air to give [CPMT 1988, 89; AFMC 1987]

Number of structural isomers of \[{{C}_{4}}{{H}_{10}}O\] are [CPMT 1983, 84, 89, 91; MADT Bihar 1984; MNR 1984; MP PET 1997; Pb. PMT 1999; MH CET 2003]

What is formed when calcium carbide react with heavy water [CPMT 1999]

Bonds present in \[CuS{{O}_{4}}.5{{H}_{2}}O\]is [IIT 1983; DCE 2001]

Which one is the strongest acid [MH CET 1999; AMU 1999,2000; Pb.CET 2001,03; MP PET 2001]

The solubility in water of sulphates down the \[Be\] group is \[Be>Mg>>Ca>Sr>Ba\]. This is due to [CBSE PMT 1995]

The compound X on reaction with \[HgS{{O}_{4}}+{{H}_{2}}S{{O}_{4}}\] gives Y which on oxidation gives acetic acid. X is [MP PMT 1999]

A compound contains atoms \[X,\,\,Y,\,\,Z.\] The oxidation number of \[X\]is \[sp-s{{p}^{2}}\] is + 5 and \[Z\] is \[-\,2\]. Therefore, a possible formula of the compound is [CPMT 1988]

The \[pH\] of 0.1 M solution of a weak monoprotic acid 1% ionized is [UPSEAT 2001; Pb. PMT 2001]

The atomic number of vanadium (V), chromium (Cr), manganese (Mn) and iron (Fe) are respectively 23, 24, 25 and 26 which one of these may be expected to have the highest second ionization enthalpy [AIEEE 2003]

In a reaction of \[{{C}_{6}}{{H}_{5}}Y,\] the major product (> 60%) is m-isomer, so the group Y is [AIIMS 1997; UPSEAT 2003]

\[Ca{{C}_{2}}+{{H}_{2}}O\to A\xrightarrow{{{H}_{2}}S{{O}_{4}}/HgS{{O}_{4}}}B\]. Identify A and B in the given reaction [CPMT 2000; BVP 2004]

Strongest intermolecular hydrogen bond is present in the following molecules pairs [IIT 1981; DCE 2000]

The degree of hydrolysis of a salt of weak acid and weak base in its 0.1 M solution is found to be 50%. If the molarity of the solution is 0.2 M, the percentage hydrolysis of the salt should be [AMU 1999]

Which of the following is the most stable cation [CBSE PMT 1988; MNR 1988; AIIMS 1985]

Toluene can be oxidised to benzoic acid by [AIIMS 1999]

As electron moves away from the nucleus, its potential energy [UPSEAT 2003]

The number of \[SS\] bonds in sulphur trioxide trimer \[{{S}_{3}}O{}_{9}\] is [IIT Screening 2001]

A precipitate of \[Ca{{F}_{2}}\,\,({{K}_{sp}}=1.7\times {{10}^{-10}})\] will be obtained when equal volume of the following are mixed [MP PMT 1990, 95; IIT 1982; MNR 1992]

Six volumes of oxygen, on complete ozonisation, form ...... volumes of ozone [DPMT 2000]

Benzene is obtained by [DPMT 2002]

The value of Planck?s constant is \[6.63\times {{10}^{-34}}Js.\] The velocity of light is \[3.0\times {{10}^{8}}\,m{{s}^{-1}}\]. Which value is closest to the wavelength in nanometres of a quantum of light with frequency of \[8\times {{10}^{15}}{{s}^{-1}}\] [CBSE PMT 2003]

The common features among the species \[C{{N}^{-}}\], CO and \[N{{O}^{+}}\] are [IIT Screening 2001]

Which of the following oxides will not give \[O{{H}^{-}}\]in aqueous solution [NCERT 1980]

When \[Mn{{O}_{2}}\] is fused with KOH, a coloured compound is formed, the product and its colour is [IIT Screening 2003]

In which block 106th element belongs [DCE 2000]

In Bohr series of lines of hydrogen spectrum, the third line from the red end corresponds to which one of the following inter-orbit jumps of the electron for Bohr orbits in an atom of hydrogen [AIEEE 2003]

\[{{N}_{2}}\] and \[{{O}_{2}}\] are converted into monocations \[N_{2}^{+}\] and \[O_{2}^{+}\] respectively. Which is wrong [CBSE PMT 1997]

\[\Delta {{H}_{f}}\,({{H}_{2}}O)=X;\] Heat of neutralisation of \[C{{H}_{3}}COOH\]and \[NaOH\] will be [BHU 2003]

The conductivity of a saturated solution of \[BaS{{O}_{4}}\] is \[3.06\times {{10}^{-6}}\,oh{{m}^{-1}}\,c{{m}^{-1}}\] and its equivalent conductance is \[1.53\,oh{{m}^{-1}}\,c{{m}^{-1}}\,equivalen{{t}^{-1}}\]. The \[{{K}_{sp}}\] of the \[BaS{{O}_{4}}\] will be [KCET 1996]

Calcium cyanide on treatment with steam under pressure gives \[N{{H}_{3}}\] and [DPMT 2002]

The number of moles of \[KMn{{O}_{4}}\] that will be needed to react completely with one mole of ferrous oxalate \[Fe({{C}_{2}}{{O}_{4}})\] in acidic solution is [IIT-JEE 1997; KCET 1996]

The following reaction is described as [CBSE PMT 1997] \[\begin{matrix} C{{H}_{3}}{{(C{{H}_{2}})}_{5}} \\ {} \\ {{H}_{3}}C \\ \end{matrix}>\underset{H}{\mathop{\underset{|}{\mathop{C}}\,}}\,-Br\xrightarrow{OH}HO-\underset{H}{\mathop{\underset{|}{\mathop{C}}\,}}\,

A group which deactivates the benzene ring towards electrophilic substitution but which directs the incoming group principally to the o- and p-positions is [Pb. PMT 1998]

Which of the following electron transition in a hydrogen atom will require the largest amount of energy [UPSEAT 1999, 2000, 01]

Volume of the air that will be expelled from a vessel of 300 \[c{{m}^{3}}\] when it is heated from \[{{27}^{o}}C\] to \[{{37}^{o}}C\] at the same pressure will be

Self-ionisation of liquid ammonia occurs as, \[2N{{H}_{3}}\]⇄\[NH_{4}^{+}+NH_{2}^{-};\,K={{10}^{-10}}\]. In this solvent, an acid might be [JIPMER 2001]