Discussion Forum



1)

The most abundant elements by mass in the body of a healthy human adult are Oxygen (61.4%); Carbon (22.9%); Hydrogen (10.0%); and Nitrogen (2.6%). The weight which 75 kg person would gain if all  1H atoms are replaced by 2H atoms is


A) 15 kg

B) 37.5 kg

C) 7.5 kg

D) 10 kg

Answer:

Option C

Explanation:

Given, the abundance of elements of mass 

       oxygen =61.4%,   carbon =22.9% hydrogen = 10.0%, nitrogen = 2.6%

Total weight of person =75 kg

              Mass due to 1H = $\frac{75\times 10}{100}=7.5$ kg

  1H   atoms are replaced by 2H atoms.

     Mass due to 2H = (7.5 × 2)kg

   $\therefore$     Mass gain by person = 7.5 kg