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QJEEM23Ch756c: JEE Main 2023 Chemistry - Class 11 JEEM23Ch756c Solution: An organic compound gives of and of on complete combustion. If…

An organic compound gives 0.220 g0.220 \mathrm{~g} of CO2\mathrm{CO}_{2} and 0.126 g0.126 \mathrm{~g} of H2O\mathrm{H}_{2} \mathrm{O} on complete combustion. If the %\% of carbon is 24 then the %\% of hydrogen is __________ ×10−1\times 10^{-1} . ( Nearest integer)

Step-by-Step Verified Solution

To find the percentage of hydrogen in the compound, we first need to determine the ratio of moles of carbon and hydrogen in the products.

The moles of CO₂ produced can be calculated by dividing the mass of CO₂ produced by its molar mass (44.01 g/mol):

moles of CO2=0.220 g44.01 g/mol=0.005 mol\text{moles of CO}_{2} = \frac{0.220 \,\mathrm{g}}{44.01 \,\mathrm{g/mol}} = 0.005 \, \mathrm{mol}

Since each mole of CO₂ contains one mole of carbon, there are 0.005 moles of carbon in the compound.

Now, let's calculate the moles of H₂O produced:

moles of H2O=0.126 g18.02 g/mol=0.007 mol\text{moles of H}_{2}\text{O} = \frac{0.126 \,\mathrm{g}}{18.02 \,\mathrm{g/mol}} = 0.007 \, \mathrm{mol}

Since each mole of H₂O contains two moles of hydrogen, there are 0.014 moles of hydrogen in the compound.

Now, let's find the masses of carbon and hydrogen in the compound:

Mass of carbon = moles of carbon × molar mass of carbon

Mass of carbon=0.005 mol×12.01 g/mol=0.060 g\text{Mass of carbon} = 0.005 \, \mathrm{mol} \times 12.01 \,\mathrm{g/mol} = 0.060 \,\mathrm{g}

Mass of hydrogen = moles of hydrogen × molar mass of hydrogen

Mass of hydrogen=0.014 mol×1.008 g/mol=0.014 g\text{Mass of hydrogen} = 0.014 \, \mathrm{mol} \times 1.008 \,\mathrm{g/mol} = 0.014 \,\mathrm{g}

Now, we are given that the percentage of carbon is 24%. Let's find the total mass of the compound:

Total mass of compound=Mass of carbon% of carbon=0.060 g0.24=0.250 g\text{Total mass of compound} = \frac{\text{Mass of carbon}}{\% \text{ of carbon}} = \frac{0.060 \,\mathrm{g}}{0.24} = 0.250 \,\mathrm{g}

Finally, let's find the percentage of hydrogen:

% of hydrogen=Mass of hydrogenTotal mass of compound×100=0.014 g0.250 g×100=5.6\% \text{ of hydrogen} = \frac{\text{Mass of hydrogen}}{\text{Total mass of compound}} \times 100 = \frac{0.014 \,\mathrm{g}}{0.250 \,\mathrm{g}} \times 100 = 5.6

So, the percentage of hydrogen is 5.6% or 56 × 10-1.

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