UPSEE Solved Model Paper 7

Given:
Number of molecules of hydrogen chloride (HCl) = 6.02 × 1025
We have to find the number of gram molecules of chlorine in 6.2 × 1025 molecules of hydrogen chloride .
1 gram molecule of any molecule contains = 6.023 × 1023 (Avogadro's constant) molecules
Thus,
1 gram molecule of HCl contains = 6.023 × 1023 (Avogadro's constant) molecules of HCl
Now, one molecule of HCl contains = One molecule of chlorine 6.023 × 1023 molecules of HCl contains = 6.023 x 1023 molecules of Chlorine
Or,
One gram molecule of HCl contains = 6.023 x 1023 molecules of Chlorine
The number of gram molecules of chlorine in 6.02 x 1025 hydrogen chloride molecules
=

6.02×1025

6.023×1023

= 100
Hence, option 'B' is correct.