Question

Five moles of helium is mixed with two moles of hydrogen to form a mixture. Take molar mass of helium $M_1=4g$ and that of hydrogen $M_2=2g$
The equivalent molar mass of mixture is:

• A. 6g
• B. $\frac{13g}{7}$
• C. $\frac{18g}{7}$
• D. none

Answer 1

The correct option is D none

Equivalent molar mass $=\frac{\sum n_i{m}_i}{\sum n_i}=\frac{\sum 5\times 4+2\times 2}{\sum 5+2}=\frac{24}{7}$.