Upon the interaction of 12 g of a divalent metal with water, the 6.72 axis of hydrogen was released. Identify the metal.

The equation for the reaction of an unknown divalent metal M with water:

M + 2H2O = M (OH) 2 + H2

Let’s find the amount of substance H2:

v (H2) = V (H2) / Vm = 6.72 / 22.4 = 0.3 (mol).

According to the reaction equation, from 1 mol of M, 1 mol of H2 is formed, therefore

0.3 mol H2 formed from 0.3 mol M.

In this way,

M (M) = m (M) / v (M) = 12 / 0.3 = 40 (amu), which corresponds to the metal calcium (Ca).