The density of ${\mathrm{NH}}_4\mathrm{OH}$ solution is found to be 0.6 g/ml. It contains 34% by weight of ${\mathrm{NH}}_4\mathrm{OH}$. Calculate the normality of the solution.

Density of ${\mathrm{NH}}_4\mathrm{OH}$ solution = 0.6 g/mL. 

That means 1ml has 0.6 g of ${\mathrm{NH}}_4\mathrm{OH}$.

1000 ml(1 L) has 600 g of ${\mathrm{NH}}_4\mathrm{OH}$
For 34% by weight of ${\mathrm{NH}}_4\mathrm{OH}$:
Mass of ${\mathrm{NH}}_4\mathrm{OH}=600\times 0.34 = 204$ 

Molecular mass of  ${\mathrm{NH}}_4\mathrm{OH}=35 g$ 

Normality of solution =$\frac{\mathrm{Given} \mathrm{mass}}{\mathrm{Molecular} \mathrm{mass}}=\frac{204}{58}= 5.8 \mathrm{N}$

Hence, the correct option is D) 5.8 N