Question

Five hundred milliliters of solution of 0.1 M $NaBr$ has how many milligrams of bromine?

• A. 200 mg
• B. 400 mg
• C. 2,000 mg
• D. 4,000 mg
• E. 20,000 mg

Answer 1

The correct option is D 4,000 mg

$1$ mole of $NaBr$ contains $80g$ of $Br$ (atomic weight of $Br$)

Now we know that,

$1000ml$, $1M$ $NaBr$ contains $1$ mole of $NaBr$,

That means,$1000ml$, $1M$ $NaBr$ contains $80g$ of $Br$.

$500ml$ $1M$ $NaBr$ contains $\frac{80}{1000}$$\times$$500$ grams of $Br$

$500ml$ $0.1M$ $NaBr$ contains $\frac{80}{1000}$$\times$$500\times 0.1$ grams of $Br$

which comes out to be equal to $4$ grams of $Br$, that is $4000mg$ of $Br$

Thus, option $D$ is the correct answer.