# How many hydrogen atoms are in each formula unit of calcium bicarbonate Ca(HCO_3)_2?

Apr 27, 2016

Looking closely at the part ${\left(H C {O}_{3}\right)}_{2}$.
It means the number of hydrogen inside the brackets $\times$ 2:
[H $\times$ 2] = ${H}_{2}$. Therefore there are two hydrogen atoms present.