set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

Which of the following statement is not correct ? To prevent food from getting rancid, we

a) flush bags of chips with an inert gas

b) store the food in air-tight containers

c) add antioxidants

d) increase the temperature of the food

Question : 2

Which one is a combination reaction ?

a) Ca(OH)₂ + Na₂CO₃ ⟶ 2NaOH + CaCO₃ ↓

b) Formation of a mixture of carbon monoxide and hydrogen. When steam is passed over red hot iron.

c) Reaction of water with sodium metal to form sodium hydroxide and hydrogen.

d) Preparation of stannic chloride (Tin (iv) chloride) by passing chlorine gas into molten tin (Sn).

Question : 3

Which of the following reaction is endothermic?

a) CH₄ + 2O₂ ⟶ CO₂ + 2H₂O

b) C + O₂ ⟶ CO₂

c) CaCO₃ ⟶ CaO + CO₂

d) CaO + H₂ O ⟶ Ca(OH)₂

Question : 4

In the reaction : PbO + C ⟶ Pb + CO

a) C is reductant

b) PbO is oxidised

c) PbO is oxidant

d) Both (a) and (c)

Question : 5

Which one is a bivalent ion?

a) sulphide

b) sodium

c) calcium

d) Both (b) and (c)

Question : 6

The molecular formula P₂O₅ means that

a) there are twice as many P atoms in the molecule as there are O atoms

b) a molecule contains 2 atoms of P and 5 atoms of O

c) the ratio of the mass of P to the mass of O in the molecule is 2:5

d) the ratio of the mass of P to the mass of O in the molecule is 5 : 2