Mole Concept & Stoichiometry · JEE Main previous year questions

2018 2 questions

1. Q802018 · 16 Apr 2018 · Shift 1

   An unknown chlorohydrocarbon has 3.55% of chlorine. If each molecule of the hydrocarbon has one chlorine atom only; chlorine atoms present in $1\mathrm{g}$ of chlorohydrocarbon are : (Atomic wt. of $\mathrm{Cl}=35.5\mathrm{u}$; Avogadro constant $=6.023\times 10^{23}\mathrm{mo}{\mathrm{l}}^{-1}$)

   1. A.$6.023\times 10^{20}$
   2. B.$6.023\times 10^9$
   3. C.$6.023\times 10^{21}$
   4. D.$6.023\times 10^{23}$
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   Answer: A

2. Q612018 · 8 Apr 2018 · Shift 1

   The ratio of mass percent of C and H of an organic compound $({\text{C}}_{\text{X}}{\text{H}}_{\text{Y}}{\text{O}}_{\text{Z}})$ is $6:1$. If one molecule of the above compound $({\text{C}}_{\text{X}}{\text{H}}_{\text{Y}}{\text{O}}_{\text{Z}})$ contains half as much oxygen as required to burn one molecule of compound ${\text{C}}_{\text{X}}{\text{H}}_{\text{Y}}$ completely to ${\text{CO}}_2$ and ${\text{H}}_2\text{O}$. The empirical formula of compound ${\text{C}}_{\text{X}}{\text{H}}_{\text{Y}}{\text{O}}_{\text{Z}}$ is

   1. A.${\text{C}}_2{\text{H}}_4{\text{O}}_3$
   2. B.${\text{C}}_3{\text{H}}_6{\text{O}}_3$
   3. C.${\text{C}}_2{\text{H}}_4\text{O}$
   4. D.${\text{C}}_3{\text{H}}_4{\text{O}}_2$
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   Answer: A