Question

A gas is found to have the formula ${\left(CO\right)}_X$ if its vapor density is 70. Find the value of X.

Answer 1

Step: 1 Introducing the formula:

Given: $\mathrm{V}.{\mathrm{D}}_{{\left(CO\right)}_X}=70$

$\mathrm{Molecular}\mathrm{Weight}=2\times \mathrm{Vapour}\mathrm{Density}$

Step: 2 Calculating the Molecular weight of the compound ${\left(CO\right)}_X$

$$\begin{gathered} \mathrm{Molecular}\mathrm{Weight}=2\times \mathrm{Vapour}\mathrm{Density} \\ \mathrm{Molecular}\mathrm{Weight}=2\times 70 \\ \mathrm{Molecular}\mathrm{Weight}=140u \end{gathered}$$

Step: 3 Calculating the value of X

Since CO is Carbon and Oxygen and their atomic weights are known and they are 12 u and 16 u.

$$\begin{gathered} {\left(CO\right)}_X=140 \\ X\left(12\right)+X\left(16\right)=140 \\ X\left(28\right)=140 \\ X=\frac{140}{28}=5 \end{gathered}$$

Therefore, the value of X is 5.