Question

Carbon dioxide formed after reaction with cupric oxide is tested by :

• A. caustic soda
• B. quick lime
• C. lime water
• D. baking soda

Answer 1

Answer: (C)

lime water

The given organic compound is mixed with dry copper oxide ($CuO$) and heated in a hard glass tube. The products of the reaction are passed over (white) anhydrous copper sulphate and then bubbled through lime water. If copper sulphate turns blue due to the formation of $CuS{O}_4.5H_{2}O$ (by water vapor) then the compound contains hydrogen. If lime water is turned milky by $C{O}_2$, then the compound contains carbon.