MCQs on Decomposition Reaction
1. CO2 obtained by the complete decomposition of 20 g CaCO3 at STP is
(a) 4.48 l
(b) 2.24 l
(c) 44.8 l
(d) 48.4 l
Answer:::: (a)
2. Decomposition of hydrogen peroxide to give H2O + O2 is an example of
(a) reduction
(b) oxidation
(c) both (a) and (b)
(d) none of the above
Answer:::: (c)
3. The reaction 2Pb(NO3)2 → 2PbO + 4NO2 + O2 is a type of _______reaction.
(a) displacement
(b) double decomposition
(c) decomposition
(d) none of the above
Answer:::: (c)
4. On passing current to an acidified water we get hydrogen and oxygen. This is a type of
(a) oxidation reaction
(b) thermal decomposition
(c) electrolysis
(d) none of the above
Answer:::: (c)
5. The correct expression for decomposition of silver chloride to silver and chlorine is
(a) AgCl2(s) → Ag(s) + 2Cl(g)
(b) 2AgCl(s)→ 2Ag(s) + Cl2(g)
(c) AgCl2(s) → Ag(s) + Cl2(g)
(d) AgCl(s) → Ag(s) + Cl(g)
Answer:::: (b)
6. A reaction where two compounds exchange their atoms to form new compounds
(a) decomposition
(b) double displacement
(c) displacement
(d) synthesis
Answer:::: (b)
7. The decomposition of silver chloride occurs by
(a) heat
(b) sunlight
(c) water
(d) electricity
Answer:::: (b)
8. How many moles of sodium carbonate is formed on decomposition of 0.2 moles of sodium bicarbonate?
(a) 0.1
(b) 0.2
(c) 0.05
(d) 0.025
Answer:::: (a)
9. Find out the volume of CO2 liberated after heating 9.85 g of BaCO3 at STP.
(a) 2.06 l
(b) 2.12 l
(c) 1.12 l
(d) 4.84 l
Answer:::: (c)
10. Ferrous sulphate on heating gives reddish-brown residue of ferric oxide. This is due to
(a) decomposition
(b) displacement
(c) combination
(d) none of the above
Answer:::: (a)
