Question

The valency of calcium in calcium hydroxide is ____.

• A. +1
• B. +2
• C. -1
• D. -2

Answer 1

The correct option is B +2

Calcium hydroxide = $Ca{\left(OH\right)}_2$

Each $O{H}^{-}$ ion has one net negative charge as oxygen has a valency of -2 and hydrogen has a valency of +1.

Now, as calcium hydroxide is a neutral compound, so it is possible only when calcium has a net positive charge of +2.

So, the valency of calcium in $Ca{\left(OH\right)}_2$ is 2.
Also, $Ca{\left(OH\right)}_2$ $\to$ ${Ca}^{2+}+2{OH}^{-}$