Question

Formula of calcium bicarbonate is $CaHC{O_3}$.
A.True
B.False

Answer 1

Hint: To answer this question the knowledge of valency is required. The valency of an element is also called the combining capacity of the element. This is equal to the number of electrons of an element taking part in bonding.

Complete step by step answer:
The charge on the bicarbonate anion is $\left( { - 1} \right)$ while the charge on the calcium ion is $\left( { + 2} \right)$ . Hence, to form a balanced compound, the calcium atom needs two electrons to balance its positive charge. This charge can be either balanced by a dipositive anion or two ions of a monopositive anion. Now as the bicarbonate anion is a monopositive anion, so two anions would be required to balance the compound.
Hence, the correct formula of calcium bicarbonate is $Ca{\left( {HC{O_3}} \right)_2}$.

So, the answer is false, or option B.

Note:
Though calcium has only one valency, there are different other elements that have multiple valences or variable valences. An example would be iron. It has two valences, one is ferrous or $\left( { + 2} \right)$ and the other is ferric $\left( { + 3} \right)$ . In such cases, the charge of the metal ion should be kept in mind before determining the formula of the salt or the compound in question. Another such example would be copper and as such, there are two oxides of copper, cupric oxide or $CuO$ in which the valency of copper is $\left( { + 2} \right)$ and the other is cuprous oxide in which the valency of copper is $\left( { + 1} \right)$ .