Question

If a sample of $MgB{r}_2$ contains $4\times {10}^{20}B{r}^{-}$ ions, then the number of $M{g}^{2+}$ ions present in it is:

• A. $4\times {10}^{20}$
• B. $8\times {10}^{20}$
• C. $2\times {10}^{20}$
• D. $1\times {10}^{20}$

Answer 1

Answer: (C)

$2\times {10}^{20}$

correct answer: option 'C'

$MgB{r}_2\to M{g}^{2+}+2B{r}^{-}$

Explanation: because the number of $M{g}^{2+}$ ions are half of $B{r}^{-}$ ions.

Therefore option 'C' is the correct answer