Question

Number of $C{a}^{2+}$ and $C{l}^{-}$ ions in anhydrous 111 g $CaC{l}_2$ are _________ (respectively)

• A. $N_A,2N_A$
• B. $2N_A,N_A$
• C. $N_A,N_A$
• D. none of these

Answer 1

Answer: (A)

$N_A,2N_A$

Molecular weight of $CaC{l}_2=40+(2\times 35.5)$ = 111 g
111 g means 1 moles of $CaC{l}_2$. Then, 1 moles of $C{a}^{2+}$ = $N_A$ molecules, 2 moles of $C{l}^{-}=2N_A$