Question

1. Before burning in air, the magnesium ribbon is cleaned by rubbing with a sand
paper to:
a. Make the ribbon surface shinier
b. Remove the layer of magnesium oxide from the ribbon surface
c. Remove the layer of magnesium carbonate from the ribbon surface
d. Remove the moisture from the ribbon surface
2. In a chemical reaction between sulphuric acid and barium chloride solution the
white precipitates formed are of:
a. Hydrochloric acid
b. Barium sulphate
c. Chlorine
d. Sulphur
3. The respiration process during which glucose undergoes slow combustion by
combining with oxygen in the cells of our body to produce energy, is a kind of:
a. Exothermic process
b. Endothermic process
c. Reversible process
d. Physical process
4. A chemical reaction does not involve:
a. Formation of new substances having entirely different properties than that of the
reactants
b. Breaking of old chemical bonds and formation of new chemical bonds
c. Rearrangement of the atoms of reactants to form new products
d. Changing of the atoms of on element into those of another element to form new
products
5. One of the following processes does not involve a chemical reaction. That is:
a. Melting of candle wax when heated
b. Burning of candle wax when heated
c. Digestion of food in our stomach
d. Ripening of banana
6. It is necessary to balance a chemical equation in order to satisfy the law of:
a. Conservation of motion
b. Conservation of momentum
c. Conservation of energy
d. Conservation of mass
7. All the methods mentioned below can be used to prevent the food from getting
rancid except:
i. Storing the food in the air-tight containers
ii. Storing the food in refrigerator

iii. Keeping the food in clean and covered containers
iv. Always touching the food with clean hands
a. (i) and (ii)
b. (i) and (iii)
c. (i), (iii) and (iv)
d. (iii) and (iv)
8. Rusting of iron involves a chemical reaction which is a combination of:
a. Reduction as well as combination reactions
b. Oxidation as well as combination reactions
c. Reduction as well as displacement reactions
d. Oxidation as well as displacement reactions
9. You are given the following chemical reaction:
Heat 2 2 CuO + H Cu + H O
This reaction represents:
a. Combination reaction as well as double displacement reaction
b. Redox reaction as well as displacement reaction
c. Double displacement reaction as well as redox reaction
d. Decomposition reaction as well as displacement reaction
10. When ferrous sulphate is heated strongly it undergoes decomposition to form
ferric oxide as a main product accompanied by a change in colour from:
a. Blue to green.
b. Green to blue.
c. Green to brown.
d. Green to yellow.
11. Which of the following gases is used in the storage of fat and oil containing
foods for a long time?
a. Carbondioxide gas
b. Nitrogen gas
c. Oxygen gas
d. Neon gas
12. The displacement reaction between iron (III) oxide and a metal X is used for
welding the rail tracks. Here X is:
a. Copper granules
b. Magnesium ribbon
c. Sodium pellets
d. Aluminium dust
13. The neutralization reaction between an acid and a base is a type of:
a. Double displacement reaction
b. Displacement reaction
c. Addition reaction
d. Decomposition reaction

14. The chemical reaction between Hydrogen sulphide and iodine to give
Hydrogen iodide and sulphur is given below:
2 2 H S + I 2HI + S
The reducing and oxidizing agents involved in this redox reaction are:
a. Iodine and sulphur respectively
b. Iodine and hydrogen sulphide respectively
c. Sulphur and iodine respectively
d. Hydrogen sulphide and sulphur
Chapter 2
ACIDS BASE AND SALTS
1. Some fruits like mango, lemon, raw grapes, orange, etc., have a sour taste due to
the presence of:
a. Acetic acid
b. Citric acid
c. Lactic acid
d. Oxalic acid
2. Zinc granules on treating with an acid X, form the zinc sulphate (ZnSO4) salt
along with the evolution of a gas Y which burns with a pop sound when brought
near to a burning candle. Identify the acid X and gas evolved Y.
a. X- Sulphuric acid and Y- Oxygen gas
b. X- Hydrochloric acid and Y- Oxygen gas
c. X- Sulphuric acid and Y- Hydrogen gas
d. X- Hydrochloric acid and Y- Hydrogen gas
3. The figure given below represents the experiment carried out between conc.
sulphuric acid and sodium chloride, which react with each other to form HCl gas.

Blue litmus paper is brought near the mouth of the delivery tube to check the
presence of HCl acid but no change is observed in the color of litmus paper
because:
a. The litmus paper used is dry
b. The litmus paper used is moist
c. Blue litmus paper does not change its color with an acid
d. The litmus paper is kept very close to the mouth of the delivery tube

Answer 1

Answer:

bro

1 -- b

because magnesium ribbon have a layer of magnesium oxide so,we clean for removing that layer