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1 Answer
Apr 2, 2018

"0.160 M"

Explanation:

Molar mass of "B"_2"Br"_6 is "501.05 g/mol"

Moles of "16 g" of "B"_2"Br"_6 is = "16 g"/"501.0 g/mol" = "0.03194 mol"

underbrace("B"_2"Br"_6) + "6HNO"_3 -> underbrace("2B(NO"_3")"_3)+ "6HBr"
color(blue)"1 mol" color(white)(.........................)color(blue)"2 mol"

From above equation, "1 mol" of "B"_2"Br"_6 on reaction with nitric acid forms "2 mol" of "B(NO"_3")"_3.

It’s given that "16 g"\ ("0.03194 mol") of "B"_2"Br"_6 is reacted

So, moles of "B(NO"_3")"_3 formed = 2 × "0.03194 mol" = "0.06388 mol"

"Molarity" = "Moles of solute"/"Volume of solution (in litres)"

"Molarity" = "0.06388 mol"/"0.4 L" = "0.1597 M" ≈ "0.160 M"