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1. Some basic concept of chemistry — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistry1. Some basic concept of chemistry1 Mark
MCQ
The average molar mass of chlorine is $35.5\, g$ $mol ^{-1}$. The ratio of $35\, Cl$ to $37 \,Cl$ in naturally occurring chlorine is close to :
  • A
    $4:1$
  • B
    $1:1$
  • C
    $2:1$
  • ✓
    $3:1$
✓

Answer

Correct option: D.
$3:1$
d
$\quad \quad{ }^{35} Cl \quad{ }^{37} Cl \quad$ Av. molar

let $\quad x \quad: \quad 1 \quad$ mass $=35.5$

mole ratio

Av. molar mass $=\frac{ n _{1} M _{1}+ n _{2} M _{2}}{\left( n _{1}+ n _{2}\right)}$

$35.5=\frac{x \times 35+1 \times 37}{x+1}$

$x=3$

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