Question

An aqueous solution of concentrated hydrobromic acid contains 48% HBr by mass. If the density of the solution is 1.5 g / mL, What is its concentration :
A: 11.4 mol / L
B: 8.9 mol / L
C: 5.9 mol / L
D: 18.5 mol /L
Please Answer Fast....

Answer 1

d= 1.50g/ml
d= m/v
Let vol. be 1000ml
m = 1000×1.5g = 1500 g
mass of HBr = 1500 ×48 /100 =
720 g
No. Of moles = 720/81= 8.9 moles
Molarity =8.9/1 =8.9 mol/ lit

Answer 2

Answer:

The correct answer is option C.

Explanation:

Hydrobromic acid contains 48% HBr by mass

In 100 g of solution  there 48 g of hydrobromic acid is present.

Volume of the solution = V

Density of the solution = 1.5 g/mL

$V=\frac{Mass}{Density}=\frac{100 g}{1.5 g/mL}=66.66 mL=0.06666 L$

$Molarity=\frac{48 g}{80.9 g/mol\times 0.06666 L}=8.90 mol/L$

The correct answer is option C.