Answer:
12*2*6.022*10^23. Atoms of hydrogen.
Explanation:
First of all if u know that 1 molecule of calcium hydroxide contain 2 hydrogen atom and 1 mole of calcium hydroxide contain 6.022*10^23 molecules of calcium hydroxide.
Hence 1 mole of calcium hydroxide contain 2*6.022*10^23 atom of hydrogen.
So 12 mole of calcium hydroxide contain =12*2*6.022*10^23. Atoms of hydrogen.