Question

. After the evaporation of seawater, the percentage of chlorine present in the impure sample of sodium chloride was found to be 36.4%. What is the percentage of sodium chloride present in the sample?

a) 50%

b) 55%

c) 60%

d)65%

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Answer 1

Molecular mass of pure NaCl = Atomic mass of Na + Atomic mass of Cl

=23+35.5=58.5 u

Percentage of chlorine in pure NaCl =(35.5u)(58.5u)×100=60.6

Now, if chlorine is 60.6 parts, NaCl = 100 parts

if chlorine is 45.5 parts, NaCl =(45.5u)(60.6u)×100=75

Thus, percentage of pure NaCl = 75 %.