PrepRung
Sign inSign up free

NDA 2018 GAT · General Knowledge · Carbon and Organic Chemistry · hard

When carbon dioxide is passed in excess through lime water, the milkiness first formed disappears because

Single correct option

When carbon dioxide is passed in excess through lime water, the milkiness first formed disappears because
  1. A. soluble calcium hydrogencarbonate is formed
  2. B. calcium oxide is formed
  3. C. calcium carbonate decomposes into calcium oxide
  4. D. calcium hydroxide is regenerated as a gas
Show answer and solution

Answer: (A) soluble calcium hydrogencarbonate is formed

A little CO2 gives insoluble calcium carbonate, which turns the lime water milky. With excess CO2, calcium carbonate reacts with CO2 and water to form soluble calcium hydrogencarbonate, so the milkiness vanishes. Calcium carbonate decomposition needs strong heating, not a room-temperature reaction.
Report a mistake

Original question written in the NDA 2018 GAT pattern and checked twice for the correct answer. Not an official question paper. How we write and check questions · Corrections policy · Report a mistake