Question

An alloy of gold and silver contains $38.5$% silver by mass and has a density of $14.6gm{L}^{-1}$.

What is the molar concentration of silver in this alloy?

• A. $52.04mol{L}^{-1}$
• B. $45.6mol{L}^{-1}$
• C. $3.57mol{L}^{-1}$
• D. $2.64mol{L}^{-1}$

Answer 1

The correct option is A $52.04mol{L}^{-1}$

The density of alloy is 14.6 g/mL.

1000 mL of the alloy will weigh $14.6\times 1000=14600g$

Out of this, 38.5 % by mass is silver.

Hence, the mass of silver present in 1000 mL of alloy is $\frac{38.5}{100}\times 14600=5621g$.

The molar mass of Ag is 108 g/mol.

Hence, the molar concentration of silver in the alloy is $\frac{5621g}{108g/mol\times 1L}=52.04mol/L$.

Hence, the correct option is $A$