Question

When excess of carbon dioxide is passed through lime water, the milkiness first formed disappears due to

• A. the reversible reaction taking place
• B. formation of water soluble calcium bicarbonate
• C. huge amount of heat evolved during the reaction
• D. formation of water soluble complex of calcium

Answer 1

Answer: (B)

formation of water soluble calcium bicarbonate

Answer 2

When excess of carbon dioxide is passed in lime water, calcium carbonate is converted to calcium bicarbonate which is soluble, hence the milkiness due to calcium carbonate disappears. $Ca(OH)_{2} +CO_{2} \to$ $\underset{\text{Milkiness}}{ {CaCO_{3}}}$ $?$CaCO_{3} + H_{2}O +CO_{2} \to$$\underset{\text{soluble}}{ {Ca(HCO_{3})_{2}}}$