Question

In the first world war, $1.1\times {10}^8$ kg of poison gas were fired on the allied forces. If the gas is assumed to be phosgene, how many molecules of the gas correspond to the amount fired on allied forces?

• A. $1.9\times {10}^{-15}$
• B. $6.7\times {10}^{32}$
• C. $2.9\times {10}^{-15}$
• D. $6.7\times {10}^{29}$

Answer 1

Answer: (B)

$6.7\times {10}^{32}$

Phosgene is $COC{l}_2$ (mol.wt =99)
99g of phosgene= $N_A$ molecules
Hence, $1.1\times {10}^{11}g=\frac{N\times 1.1\times {10}^{11}}{99}$
$=6.7\times {10}^{32}$.