Answer :
What you have to do it find the percentage / solve it. Divide the mass by the entire mass.
239.7 ÷ 266.68 = 0.898 × 100 = 90% Br.
239.7 ÷ 266.68 = 0.898 × 100 = 90% Br.
Answer: The correct answer is option(4).
Explanation:
Molar mass of the aluminium bromide, [tex]AlBr_3=266.69 g/mol[/tex]
Atomic mass of bromine = 79.90 g/mol
Percentage of Mass of bromine in [tex]AlBr_3[/tex]:
[tex]\% Br\text{ by mass}=\frac{\text{Atomic mass of Br}\times \text{Number of Br atoms}\times 100}{\text{Molar mass of }AlBr_3}[/tex]
[tex]\% Br\text{ by mass}=\frac{79.90 g/mol\times 3\times 100}{266.69 g/mol}=89.97\%\approx 90\%[/tex]
Hence, the correct answer is option(4).
