Question

What percentage of the total mass of $KH{CO}_3$ is made up by nonmetallic elements?

• A. 17%
• B. 83%
• C. 61%
• D. 20%
• E. 50%

Answer 1

Answer: (C)

61%

The portion of non-metals in $KHC{O}_3$ is $HC{O}_3$, as $K$ is metal.
Molar weight of $HC{O}_3$ = $1+12+3\times 16=61$
Molar weight of $K=39$
Hence, percentage of non-metal present = $\frac{61}{39+61}\times 100=61$%.