Explore topic-wise MCQs in Science.

This section includes 25 Mcqs, each offering curated multiple-choice questions to sharpen your Science knowledge and support exam preparation. Choose a topic below to get started.

1.

All samples of pure water contain hydrogen and oxygen in the mass ratio of\[1:8\].To which of the following laws does the above statement is in agreement?

A.  Law of conservation of mass
B.  Law of constant proportion  
C.  Pivot joint 
D.  Law of definite proportion
Answer» C.  Pivot joint 
2.

Calculate the weight in grams present in \[0.7\] moles of sodium.

A. \[16.1\,\,g\] 
B. \[16.2\,\,g\]
C.  Flightless
D. \[0.161\,\,g\]
Answer» B. \[16.2\,\,g\]
3.

What weight of calcium contains the same number of atoms as those in \[3\text{ }g\] of carbon?

A. \[10\,\,g\]  
B. \[20\,\,g\]
C. Flamingo  
D. \[40\,\,g\]
Answer» B. \[20\,\,g\]
4.

The isotopes contain the same number of____ and different number of______.

A. Neutrons, Protons
B. Electrons, Protons
C.  tail feathers with the breast bone
D. Neutrons, Protons
E. None of these
Answer» D. Neutrons, Protons
5.

Number of atoms present in \[5g\] of \[NaN{{O}_{3}}\]is:

A. \[1.8\times {{10}^{24}}\] atoms 
B. 3.54 atoms
C. 1-B 2-C  3-A 4-D
D. \[1.54\times {{10}^{23}}\] atoms
E. None of these
Answer» D. \[1.54\times {{10}^{23}}\] atoms
6.

Calculate the mass of \[{{H}_{2}}{{O}_{2}}\] contained in \[0.4\] mole of\[{{H}_{2}}{{O}_{2}}\].

A. 18.2 g  
B. 13.6 g
C. Crow 
D. 18.4.
E. None of these
Answer» C. Crow 
7.

How many grams of sodium oxalate are to be weighed to get 0.1 mole of sodium oxalate\[(N{{a}_{2}}{{C}_{2}}{{O}_{4}})\]?

A.  \[13.4\,\,g\]  
B.  \[1.34\,\,g\]
C. Beak and legs 
D.  \[0.134\,\,g\]
Answer» B.  \[1.34\,\,g\]
8.

The percentage of sulphur in sulphuric acid is :

A. 40% 
B. 0.326
C. Eagle   
D. 0.35
E. None of these
Answer» C. Eagle   
9.

The term ?mole? in chemistry was introduced by who of the following.

A. Lavosier 
B. Wilhelm Ostwald
C.  Beak and legs  
D. Neil Bohr
E. None of these
Answer» C.  Beak and legs  
10.

Number of atoms in 69 g of Na is :

A. \[1.0\times {{10}^{24}}\] atoms of Na
B. \[1.80\times {{10}^{24}}\] atoms of Na
C. 1 and 3 only  
D. \[1.5\times {{10}^{23}}\] atoms of Na
E. None of these
Answer» C. 1 and 3 only  
11.

Calculate the number of sulphur molecules in a 300 g sample of sulphur \[[{{S}_{8}}].\]

A. \[7.7\times {{10}^{20}}\,molecules\]
B. \[7.05\times {{10}^{23}}\,molecules\]
C. A-2   B-3   C-1  D-4
D. \[6.023\times {{10}^{23}}\,molecules\]
E. None of these
Answer» C. A-2   B-3   C-1  D-4
12.

Molar mass of \[{{C}_{2}}{{H}_{4}}\] is:

A. \[26\,g\,mo{{l}^{-1}}\]
B. \[28\,g\,mo{{l}^{-1}}\]
C. fly high   
D. \[32\,g\,mo{{l}^{-1}}\]
E. None of these
Answer» C. fly high   
13.

The number of electrons present in M shell of chlorine is:

A. 8   
B. 7
C.  A bird that makes her nest using stones and pebbles on ground
D. 18
E. None of these
Answer» C.  A bird that makes her nest using stones and pebbles on ground
14.

A molecular formula is a short form representation of\['X'\]. Identify \['X'\] from the following.

A.  A compound  
B.  An element
C. d e f g Nectar Flesh Muddy water with insects Seeds    
D.  An alloy
Answer» B.  An element
15.

Which one of the following was not explained in Rutherford's nuclear model of atom?

A. An atom consists of tiny positively charged nucleus surrounded by negatively charged electrons.
B. Stability of an atom.
C.    
D. The number of electrons and protons are equal in an atom.
E. None of these
Answer» C.    
16.

16 g of water is equal to ____ moles.

A. 1.2 
B. 1.9 mol
C. Ashok, Beena, Shuchi and Siddhi only
D. 8.8 mol
E. None of these
Answer» D. 8.8 mol
17.

Cathode rays are:

A. Negatively charged   
B. Positively charged
C. It makes the beak strong and is used for cracking seeds.
D. All above
E. None of these
Answer» B. Positively charged
18.

Sulphate of divalent metal M exists in hydrated form. If 0.10 mol of metal sulphate combines with 9.0 g of water to form the hydrated salt then, the formula of metal sulphate will be

A. \[\text{MS}{{\text{O}}_{\text{4}}}\text{.}{{\text{H}}_{\text{2}}}\text{O}\]
B. \[{{\text{M}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}\text{.2}{{\text{H}}_{\text{2}}}\text{O}\]   
C.  birds do not take care of their young ones
D. \[\text{MS}{{\text{O}}_{\text{4}}}\text{.5}{{\text{H}}_{\text{2}}}\text{O}\]
Answer» E.
19.

Calculate the number of moles of helium present in\[6.46\,\,g\]. (The atomic weight of helium is\[4\,\,a.m.u.\]).

A.  \[16.15\] moles  
B.  \[1.615\] moles  
C. Ground  
D.  \[0.1615\] moles
Answer» C. Ground  
20.

Direction: Observe the given flow chart and answer the following question.What are c and d?

A. c = multiply by \[{{\text{N}}_{\text{A}}}\], d = divide by \[{{\text{N}}_{\text{A}}}\]
B. c = multiply by \[{{\text{N}}_{\text{A}}}\], d = multiply by \[{{\text{N}}_{\text{A}}}\]
C.  Partridge   
D. c = divide by \[{{\text{N}}_{\text{A}}}\], d = divide by \[{{\text{N}}_{\text{A}}}\]
Answer» D. c = divide by \[{{\text{N}}_{\text{A}}}\], d = divide by \[{{\text{N}}_{\text{A}}}\]
21.

Which of the following represents the correct number of moles of each element in 40 g of ferric sulphate? [Atomic mass of Fe = 56 u, S = 32 u, 0 = 16 u]

A. Fe S 0 2 3 12
B. Fe S 0 1 1 4
C. swimming bird
D. Fe S 0 0.1 0.1 0.4
Answer» D. Fe S 0 0.1 0.1 0.4
22.

Calculate the number of atoms present in \[6.4\,\,g\] of sulphur.

A.  \[2.4\times {{10}^{-23}}\]atoms
B.  \[2.4\times {{10}^{-23}}\]atoms
C.  On snowy mountains
D.  \[1.2\times {{10}^{-23}}\]atoms
Answer» D.  \[1.2\times {{10}^{-23}}\]atoms
23.

Which one of the following fundamental particles is negatively charged?

A. Electron
B. Proton
C.  a duck has broad and flat beak with strainers  
D. All the above
E. None of these
Answer» B. Proton
24.

Select the relation between atomic number, mass number and number of neutrons.

A. Mass number = atomic number + number of neutrons
B. Mass number = atomic number/number of neutrons
C.  long, slender and curved beak
D. Mass number = atomic number - number of neutrons
E. None of these
Answer» B. Mass number = atomic number/number of neutrons
25.

Which of the following shells can hold maximum number of electrons?

A. M  
B. N
C.  1-B, 2-A, 3-D, 4-C  
D. K
E. None of these
Answer» C.  1-B, 2-A, 3-D, 4-C