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# Important Questions (2 marks): Chemical Reactions And Equations

## 20 Questions MCQ Test Science Class 10 | Important Questions (2 marks): Chemical Reactions And Equations

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This mock test of Important Questions (2 marks): Chemical Reactions And Equations for Class 10 helps you for every Class 10 entrance exam. This contains 20 Multiple Choice Questions for Class 10 Important Questions (2 marks): Chemical Reactions And Equations (mcq) to study with solutions a complete question bank. The solved questions answers in this Important Questions (2 marks): Chemical Reactions And Equations quiz give you a good mix of easy questions and tough questions. Class 10 students definitely take this Important Questions (2 marks): Chemical Reactions And Equations exercise for a better result in the exam. You can find other Important Questions (2 marks): Chemical Reactions And Equations extra questions, long questions & short questions for Class 10 on EduRev as well by searching above.
QUESTION: 1

### Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride. This is a:

Solution: Reaction of magnesium with nitrogen is a combination reaction as these two reactants (Mg and N2) combine to form a single product as magnesium nitride (Mg3N2). The equation can be written as: 3Mg(s) + N2(g) → Mg3N2(s).

QUESTION: 2

### Which of the following pairs will give a displacement reaction?

Solution: Copper metal is more reactive than silver nitrate to displace silver and form copper nitrate.

2AgNO3 + Cu → Cu (NO3)2 + 2Ag

QUESTION: 3

### Consider the reactions CUSO4 + Fe → FeSO4 + Cu  FeSO4 + Zn → ZnSO4 + Fe

Solution:

Metals present on top of the other metal in the activity series can displace the metal at the bottom from its salt solution. So zinc is present at the top of the iron and can displace iron from its sulphate solution.

QUESTION: 4

Which among the following is a double displacement?

Solution: A metathesis reaction is also called a double displacement reaction is a chemical process involving the exchange of ions of cations and anions between reacting species resulting in the creation of two new chemical species. These are many types like precipitation reaction, neutralization reaction etc.

QUESTION: 5

Rahul took some zinc granules in a test tube and added dilute HCl to it. He observed that the colour of zinc granules changed to

Solution:
QUESTION: 6

When a solution of barium chloride in water is added to an aqueous solution of sodium sulphate, the following happens :

Solution: BaCl2 (aq) + Na2SO4 (aq) → BaSO4 (s) + 2NaCl (aq)

White ppt

QUESTION: 7

On keeping iron nails in copper sulphate solution for two hours, the colour of solution changes

Solution:
QUESTION: 8

Iron sulphate crystals on heating show the evolution of gas which

Solution: SO2 and SO3 gases are evolved which cause choking and suffocation.

QUESTION: 9

Four students were asked to study the reaction between aqueous solutions of barium chloride and sodium sulphate. On mixing the solutions of the two salts in a test tube, they reported their experiment as follows:

(i) The colour of the mixture becomes brown

(ii) The solutions form a separate layer

(iii) a colourless mixture is obtained.

(iv) a white substance settles at the bottom.

The correct report is

Solution: BaCl2 (aq) + Na2SO4 (aq) → BaSO4 (s) + 2NaCl (aq)

White ppt of BaSO4 settles at the bottom.

QUESTION: 10

A small amount of quick lime is taken in a beaker. Water is added slowly to the beaker. Which of the following were noted?

Solution: The reaction is exothermic and heat is produced with hissing sound.

QUESTION: 11

Products obtained as a result of double displacement reaction using BaCl2 and Na2SO4 are:

Solution: BaCl2 + Na2SO4 → BaSO4 + 2NaCl

QUESTION: 12

Astha added quick lime to water and observed that heat is produced. The kind of this reaction is:

Solution: A lot of heat is produced in the reaction, which may even cause the water to boil. Hence it is a combination reaction as well as exothermic reaction.

QUESTION: 13

On heating crystals of ferrous sulphate, products obtained are:

Solution: On heating, ferrous sulphate crystals lose water and anhydrous ferrous sulphate (FeSO4) is formed. So their colour changes from light green to white. On further heating, anhydrous ferrous sulphate decomposes to form ferric oxide (Fe2O3), sulphur dioxide (SO2) and sulphur trioxide (SO3).

QUESTION: 14

In which form zinc metal is used from the laboratory to prepare hydrogen?

Solution:

Hydrogen is prepared in the lab by the action of acids on metals dilute. Sulphuric acid is added to granulated zinc. Zinc sulphate or zinc chloride is formed in solution and the hydrogen that is evolved is collected over water in a trough.

QUESTION: 15

Which of the following solutions is coloured?

Solution:
QUESTION: 16

Aqueous solution of which of the following is colourless?

Solution:
QUESTION: 17

A student placed a Zn rod in the FeSO4 solution. After 10 hours when the rod was taken out and it was observed that:

Solution:
QUESTION: 18

Aradhita added zinc granules in iron sulphate solution, and made a few observations. Identify the incorrect observation.

(i) Pale green solution becomes colourless.

(ii) Black deposit seen on zinc granules.

(iii) Red deposit seen on zinc granules.

(iv) Colourless solution becomes pale green.

Solution:
QUESTION: 19

Sapna added a strip of aluminium to 50 mL of a solution of FeSO4 in a test tube. The correct observation for change in colour of solution made by her is:

Solution:
QUESTION: 20

The reaction :

Fe2O3 + 2Al → Al2O3 + 2Fe is an example of

Solution:

In the chemical reaction Fe2O3 + 2Al → Al2O3 + 2Fe

The above reaction is known as displacement reaction iron oxide reacts with aluminium to form aluminium oxide and iron metal.