Question

Which of the reactions represents "slaking of lime" ?

• A. $CaC{O}_3\rightleftharpoons CaO+C{O}_2$
• B. $CaO+C{O}_2\to CaC{O}_3$
• C. $CaO+H_{2}O\to Ca(OH{)}_2$
• D. $CaO+Si{O}_2\to CaSi{O}_3$

Answer 1

Answer: (C)

The word slaking means the addition of water to calcium oxide powder (lime). The resulting product is calcium hydroxide. (milk of lime)
$CaO+H_{2}O\to Ca(OH{)}_2$
The reaction is exothermic, so the mixture heats up. Slaking is a key step in the most widely used procedure for formation of precipitated calcium carbonate.