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QJEEM22Ch3ba7: JEE Main 2022 Chemistry - Class 11 JEEM22Ch3ba7 Solution: A sample of 4.5 mg of an unknown monohydric alcohol, R-OH was…

A sample of 4.5 mg of an unknown monohydric alcohol, R-OH was added to methylmagnesium iodide. A gas is evolved and is collected and its volume measured to be 3.1 mL. The molecular weight of the unknown alcohol is __________ g/mol. [Nearest integer]

Step-by-Step Verified Solution

R−OH+CH3Mgl⇒R−OMgl+CH4

moles of alcohol (ROH)≡(\mathrm{ROH}) \equiv moles of CH4\mathrm{CH}_{4}

At STP,      [Assuming STP]

1 mole corresponds to 22.7 L

Hence, 3.1 mL≡3.122700 mol

So, moles of alcohol =3.122700

⇒3.122700=4.5×10−3M

M≃33 g/mol

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