WAEC Chemistry 2011 Theory — Question 23
Question 23 of 31 from the West African Examinations Council (WAEC) Chemistry 2011 Theory paper, with the correct answer and a full explanation.
Advertisement
7(c) Give the reason why: (i) dilute H2SO4 is not suitable for the preparation of CO2(g) from CaCO3(s); (ii) concentrated H2SO4 cannot be used to dry ammonia gas.
Model answer
(i) CaCO3 reacts with H2SO4 to form CaSO4, which is insoluble in water. The insoluble layer of CaSO4 covers the CaCO3, preventing further reaction. (ii) Concentrated H2SO4 cannot be used to dry ammonia gas because the two react: H2SO4+2NH3→(NH4)2SO4.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.