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This section includes 2637 Mcqs, each offering curated multiple-choice questions to sharpen your 7th Class knowledge and support exam preparation. Choose a topic below to get started.
| 701. |
DIRECTIONS: Read the passage given below and answer the questions that/allow. Passage - 2 Salt dissolved in water forms solution. Salt holding capacity of water is limited. When this limit is reached the solution is said to be saturated. Excess salt, if any, separates out from a saturated solution in the form of salt crystals. These crystals are more than 90% pure. We make use of the process of crystallization for obtaining salt from sea water A solution in which no more solute can be dissolved is called |
| A. | unsaturated solution |
| B. | saturated solution |
| C. | true solution |
| D. | None of these |
| Answer» C. true solution | |
| 702. |
DIRECTIONS: Read the passage given below and answer the questions that/allow. Passage - 2 Salt dissolved in water forms solution. Salt holding capacity of water is limited. When this limit is reached the solution is said to be saturated. Excess salt, if any, separates out from a saturated solution in the form of salt crystals. These crystals are more than 90% pure. We make use of the process of crystallization for obtaining salt from sea water The process of crystallization is used to obtain pure compound from an impure sample. Which of the following statements is correct? |
| A. | Process of crystallization is an example of a chemical change. |
| B. | Process of crystallization is an example of a physical change. |
| C. | Process of crystallization involves an irreversible change. |
| D. | All the above are correct. |
| Answer» C. Process of crystallization involves an irreversible change. | |
| 703. |
DIRECTIONS: Read the passage given below and answer the questions that/allow. Passage - 2 Salt dissolved in water forms solution. Salt holding capacity of water is limited. When this limit is reached the solution is said to be saturated. Excess salt, if any, separates out from a saturated solution in the form of salt crystals. These crystals are more than 90% pure. We make use of the process of crystallization for obtaining salt from sea water. The crystals that are obtained after crystallization are: |
| A. | 10%pure |
| B. | between 20% to 50% pure |
| C. | between 50% to 90% pure |
| D. | more than 90% pure |
| Answer» E. | |
| 704. |
DIRECTIONS: Read the passage given below and answer the questions that/allow. Passage - 1 Take a small quantity of copper sulphate crystals and dissolve it in a small quantity of water to obtain blue coloured solution. Add a few drops of dilute sulphuric acid. Now, put 3-5 medium sized iron nails in it. Soon the colour of blue solution changes to green and a brown deposit appears on the iron nails. Brown deposits that appears on iron nails Is due to deposition of: |
| A. | iron on iron nails |
| B. | copper on iron nails |
| C. | copper sulphate on iron nails |
| D. | iron sulphate on iron nails |
| Answer» C. copper sulphate on iron nails | |
| 705. |
Which of the following will be observed if an apple slice is left exposed to air? |
| A. | It under goes oxidation and become brown in colour |
| B. | Appearance of brown colour on the surface of apple slice is caused by a chemical reaction between air and enzymes |
| C. | Both the above are correct |
| D. | None of these |
| Answer» D. None of these | |
| 706. |
Match column I with column II and select the correct option from the codes given below. Column I Column II (P) Expansion of metals on heating (i) Neither physical nor chemical change (Q) A stone kept in the sunlight (ii) Chemical change (R) Burning of a candle (iii) Combination of physical and chemical changes (S) Curdling of milk (iv) Physical change |
| A. | (P)-(iv), (Q)-(i), (R)-(iii), (S)-(ii) |
| B. | (P)-(iv), (Q)-(iii), (R)-(ii), (S)-(i) |
| C. | (P)-(i), (Q)-(ii), (R)-(iii), (S)-(iv) |
| D. | (P)-(i), (Q)-(iv), (R) - (ii), (S)-(iii) |
| Answer» B. (P)-(iv), (Q)-(iii), (R)-(ii), (S)-(i) | |
| 707. |
Why is the rusting of iron grouped under a chemical change? |
| A. | It changes its colour. |
| B. | It becomes powdery. |
| C. | A new substance is formed. |
| D. | It changes its shape. |
| Answer» D. It changes its shape. | |
| 708. |
DIRECTIONS: Read the passage given below and answer the questions that/allow. Passage - 1 Take a small quantity of copper sulphate crystals and dissolve it in a small quantity of water to obtain blue coloured solution. Add a few drops of dilute sulphuric acid. Now, put 3-5 medium sized iron nails in it. Soon the colour of blue solution changes to green and a brown deposit appears on the iron nails. Green colour of the solution is due to the formation of.................... |
| A. | Copper sulphate |
| B. | Iron sulphate |
| C. | Copper metal |
| D. | none of these |
| Answer» C. Copper metal | |
| 709. |
Which of the following changes does food in a refrigerator undergo? |
| A. | Slow, physical change |
| B. | Slow, chemical change |
| C. | Fast, chemical change |
| D. | Fast, physical change |
| Answer» C. Fast, chemical change | |
| 710. |
On sprinkling salt on an ice cube, it starts melting. What change does the cube of ice undergo? |
| A. | Physical change |
| B. | Chemical change |
| C. | Molecular change |
| D. | Permanent change |
| Answer» B. Chemical change | |
| 711. |
DIRECTIONS: Match Column-I with Column-II and select the correct answer using the codes given below the columns. Column - I Column - II (A) Pasteurization of milk (p) Physical change (B) Explosion of fireworks (q) Rusting of iron (C) A chemical equation (r) Physical change (D) Formation of iron oxide (s) \[Magnesium\text{ }\left( Mg \right)+Oxygen~({{O}_{2}})\to Magnesium\,oxide\,(MgO)\] |
| A. | (A) \[\to \] (s), (B) \[\to \] (p), (C) \[\to \] (q), (D) \[\to \] (r) |
| B. | (A) \[\to \] (r), (B) \[\to \] (p), (C) \[\to \] (s), (D) \[\to \] (q) |
| C. | (A) \[\to \] (r), (B) \[\to \] (p), (C) \[\to \] (q), (D) \[\to \] (s) |
| D. | (A) \[\to \] (p), (B) \[\to \] (r), (C) \[\to \] (s), (D) \[\to \] (q) |
| Answer» C. (A) \[\to \] (r), (B) \[\to \] (p), (C) \[\to \] (q), (D) \[\to \] (s) | |
| 712. |
Karuna wrapped some green gram pulses in a wet cotton cloth and when she observed them after a couple of days, she found small white growths on them. What could be this change? |
| A. | Physical change |
| B. | Temporary change |
| C. | Chemical change |
| D. | Periodic change |
| Answer» D. Periodic change | |
| 713. |
Malleability is a property by which: |
| A. | Metals can be burnt. |
| B. | Metals can be stretched into wires. |
| C. | Metal can be converted into thin sheets. |
| D. | All the above |
| E. | None of these |
| Answer» D. All the above | |
| 714. |
DIRECTIONS: Match Column-I with Column-II and select the correct answer using the codes given below the columns. Column - I Column - II (A) heat energy is evolved during the reaction (p) Physical change (B) Heat energy is absorbed (q) Chemical change (C) Digestion of food in the body (r) Exothermic reaction (D) Melting of wax (s) Endothermic reaction |
| A. | (A) \[\to \] (p), (B) \[\to \] (q), (C) \[\to \] (r), (D) \[\to \] (s) |
| B. | (A) \[\to \] (q), (B) \[\to \] (p), (C) \[\to \] (r), (D) \[\to \] (s) |
| C. | (A) \[\to \] (r), (B) \[\to \] (s), (C) \[\to \] (p), (D) \[\to \] (q) |
| D. | (A) \[\to \] (r), (B) \[\to \] (s), (C) \[\to \] (q), (D) \[\to \] (p) |
| Answer» E. | |
| 715. |
Three substances given below are kept in the open for a few days. Which of them will undergo a chemical change? |
| A. | Eggs |
| B. | Plastic bottle |
| C. | Both eggs and moth balls |
| D. | Eggs, plastic bottle and moth balls |
| Answer» B. Plastic bottle | |
| 716. |
Rate of rusting of iron will be more in: |
| A. | Deserts |
| B. | Coastal areas |
| C. | Polar regions |
| D. | All the above |
| E. | None of these |
| Answer» C. Polar regions | |
| 717. |
What is the formula of rust? |
| A. | \[\text{F}{{\text{e}}_{\text{3}}}{{\text{O}}_{\text{4}}}\] |
| B. | \[\text{F}{{\text{e}}_{\text{2}}}{{\text{O}}_{\text{3}}}\] |
| C. | \[\text{FeO}\] |
| D. | None of these |
| Answer» C. \[\text{FeO}\] | |
| 718. |
Complete the following equation of rusting of iron. \[\text{Iron(Fe)+A+moisture}\to \text{B}\] |
| A. | A = Oxygen, B = Carbon dioxide |
| B. | A = Water, B = Oxygen |
| C. | A = Oxygen, B = Rust (iron oxide) |
| D. | A = Carbon dioxide, B = Oxygen |
| Answer» D. A = Carbon dioxide, B = Oxygen | |
| 719. |
Read the following statements carefully and then select the correct answer. 1. An Iron ball which can pass through a ring easily may not do so when heated. 2. When seeds are soaked in water, they absorb water and grow bigger. |
| A. | Both the statements 1 and 2 indicate physical changes. |
| B. | Both the statements 1 and 2 indicate chemical changes. |
| C. | Statement 1 shows a physical change while statement 2 shows a chemical change. |
| D. | Statement 1 shows a chemical change while statement 2 shows a physical change. |
| Answer» D. Statement 1 shows a chemical change while statement 2 shows a physical change. | |
| 720. |
Which of the following suffers maximum damage due to the rusting of iron? |
| A. | 2 |
| B. | 1 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 721. |
Which coloured light is produced when magnesium ribbon bums? |
| A. | Yellow light |
| B. | Red bright light |
| C. | Brilliant white light |
| D. | Black light |
| E. | None of these |
| Answer» D. Black light | |
| 722. |
Which one of the following substance is a mixture? |
| A. | Copper |
| B. | Salt |
| C. | Sugar |
| D. | Muddy water |
| Answer» E. | |
| 723. |
Observe the following figures. Identify the type of change. |
| A. | Physical change |
| B. | Chemical change |
| C. | Reversible change |
| D. | Periodic change |
| Answer» C. Reversible change | |
| 724. |
What change is observed when a piece of magnesium wire is burnt? |
| A. | Physical change |
| B. | Chemical change |
| C. | Nuclear change |
| D. | Both (A) and (B) |
| Answer» C. Nuclear change | |
| 725. |
Sagging of electric wires in summers is because of: |
| A. | Contraction of metals on heating. |
| B. | Expansion of metals on heating. |
| C. | Metals remain same on heating. |
| D. | Metals change their colour on heating. |
| E. | None of these |
| Answer» C. Metals remain same on heating. | |
| 726. |
Which of the following is not a mixture? |
| A. | Air |
| B. | Pure water |
| C. | Sea water |
| D. | Lemonade |
| Answer» C. Sea water | |
| 727. |
A change is a chemical change when it is accompanied by: |
| A. | energy change |
| B. | formation of new substances |
| C. | change in chemical properties |
| D. | All of the above |
| Answer» E. | |
| 728. |
Vishakha took few wire pieces made up of different metals and placed them in blue solution of copper sulphate. What will be the changes in the colour of the solutions present in beakers I, II and III? |
| A. | I II III Green Blue Green |
| B. | I II III Blue Green Green |
| C. | I II III Green Blue Blue |
| D. | I II III Blue Blue Blue |
| Answer» D. I II III Blue Blue Blue | |
| 729. |
\[NaHC{{O}_{3}}\]is: |
| A. | Washing soda |
| B. | Baking soda |
| C. | Alum |
| D. | Rust |
| E. | None of these |
| Answer» C. Alum | |
| 730. |
Complete the following analogy Electrolyzing: chemical change :: crystallization |
| A. | Thermal change |
| B. | Physical change |
| C. | Neutralization |
| D. | Fast change |
| Answer» C. Neutralization | |
| 731. |
Process by which salt is obtained by the evaporation of sea water. |
| A. | Sublimation |
| B. | Condensation |
| C. | Galvanisation |
| D. | Crystallisation |
| E. | None of these |
| Answer» E. None of these | |
| 732. |
Which of the following will be true of 'ash? that is obtained by burning wood in air? |
| A. | Some properties of ash will not be similar to wood. |
| B. | The properties of ash will be similar to wood. |
| C. | The properties of ash will be different from both wood and air. |
| D. | The properties of ash will be similar to both wood and air. |
| Answer» D. The properties of ash will be similar to both wood and air. | |
| 733. |
______ is not a physical property of a substance. |
| A. | Colour |
| B. | Shape |
| C. | State |
| D. | Flammability |
| E. | None of these |
| Answer» E. None of these | |
| 734. |
Which of the following is necessary for rusting of iron? |
| A. | Water |
| B. | Air |
| C. | Heat energy |
| D. | Both (a) and (b) |
| Answer» E. | |
| 735. |
Look at the following reaction and choose the correct statement. \[Ca{{(OH)}_{2}}+C{{O}_{2}}\to CaC{{O}_{3}}+{{H}_{2}}O\] |
| A. | \[C{{O}_{2}}\]Turns lime water milky. |
| B. | White coloured insoluble calcium carbonate is formed. |
| C. | It is a physical change. |
| D. | Both [a] and [b] |
| E. | None of these |
| Answer» E. None of these | |
| 736. |
Which of the processes below involves change in state? |
| A. | Evaporation |
| B. | Condensation |
| C. | Sublimation |
| D. | All of the above |
| Answer» E. | |
| 737. |
___ is known as blue vitriol. |
| A. | Potassium sulphate |
| B. | Iron sulphate |
| C. | Crystals of copper sulphate |
| D. | Copper hydroxide |
| E. | None of these |
| Answer» D. Copper hydroxide | |
| 738. |
When a substance undergoes a physical change, what change is seen in its mass? |
| A. | It increases. |
| B. | It decreases. |
| C. | It remains the same. |
| D. | It either increases or decreases. 4 |
| Answer» D. It either increases or decreases. 4 | |
| 739. |
Which of the following is not a Combination reaction? |
| A. | \[2\,\,Mg+{{O}_{2}}\to 2\,\,MgO\] |
| B. | \[{{N}_{2}}+3{{H}_{2}}\to 2N{{H}_{3}}\] |
| C. | \[Ca{{(OH)}_{2}}\to CaO+{{H}_{2}}O\] |
| D. | \[2{{H}_{2}}+{{O}_{2}}\to 2{{H}_{2}}O\] |
| E. | None of these |
| Answer» D. \[2{{H}_{2}}+{{O}_{2}}\to 2{{H}_{2}}O\] | |
| 740. |
Pooja took a candle in a vessel and heated the vessel. Even though the candle did not bum, it changed its shape and state. What kind of change is this? |
| A. | Irreversible change |
| B. | Physical change |
| C. | Chemical change |
| D. | None of these |
| Answer» C. Chemical change | |
| 741. |
What kind of change is undergone by the burning of wax? |
| A. | Physical change |
| B. | Chemical change |
| C. | Reversible change |
| D. | Periodic change |
| Answer» C. Reversible change | |
| 742. |
Why rusting of iron is a chemical change? |
| A. | Because it changes its colour |
| B. | Because it makes iron powdery |
| C. | Because a new substance is formed |
| D. | None of these |
| Answer» D. None of these | |
| 743. |
Which of the following is NOT correctly paired? |
| A. | Sublimation - Physical change |
| B. | Precipitation - Physical change |
| C. | Decomposition - Chemical change |
| D. | Decantation - Chemical change |
| Answer» E. | |
| 744. |
Glowing of an electric bulb is a ________ change. |
| A. | physical |
| B. | chemical |
| C. | Both physical and chemical |
| D. | None of these |
| Answer» B. chemical | |
| 745. |
Original substances participating in a chemical reaction are __ and the new substances formed are known as the ____. |
| A. | Products, reactants |
| B. | Catalysts, Reactants |
| C. | Reactants, products |
| D. | Products, Catalysts |
| E. | None of these |
| Answer» D. Products, Catalysts | |
| 746. |
In which one of the following situations chemical reaction does not occur? |
| A. | Common salt is exposed to air |
| B. | Coal is burnt in air |
| C. | Sodium is placed in water |
| D. | Iron is kept in moist air |
| Answer» B. Coal is burnt in air | |
| 747. |
During the science activity, Ms Prabha demonstrated an experiment in following steps: Step 1: She burned a substance X over the candle flame and white dazzling light was observed. Also white powdery ash was left behind. Step 2: She mixed the white ash formed with small amount of water. Then she dipped red and blue litmus papers into the solution one by one. Which of the following observations are correct? I. The substance burned in step 1 was magnesium. II. The white ash formed in step 1 was magnesium oxide. III. The solution formed in step 2 was acidic in nature IV. The solution formed in step 2 turned blue litmus red. |
| A. | I and II only |
| B. | III and IV only |
| C. | I, II and III only |
| D. | II, III and IV only |
| Answer» B. III and IV only | |
| 748. |
If freezing point of ice is \[32{}^\circ \] F then find the freezing point of ice in Kelvin? |
| A. | \[0\,\,K\] |
| B. | \[273.15\,\,K\] |
| C. | \[272\,\,K\] |
| D. | \[373\,\,K\] |
| E. | None of these |
| Answer» C. \[272\,\,K\] | |
| 749. |
When ice is heated, it changes to water and water on further heating gets converted to steam. What happens when steam is condensed? |
| A. | A new substance is formed |
| B. | No new substance is formed |
| C. | Gaseous phase changes to liquid phase |
| D. | Both (b) and (c) are correct |
| Answer» E. | |
| 750. |
Which of the following statements is correct about the given changes? (i) Drawing copper into a wire (ii) Breaking of a glass (iii) Heating an iron nail till red hot (iv) Inflating a basketball |
| A. | (i) and (ii) are chemical changes while (iii) and (iv) are physical changes. |
| B. | (ii) and (iii) are chemical changes while (i) and (iv) are physical changes. |
| C. | All are physical changes. |
| D. | All are chemical changes. |
| Answer» D. All are chemical changes. | |