112 ml of gas is produced at STP by the action of 0.412 gm of ROH alcohol with CH3Mgl. The molecular mass of alcohol is:

Explanation

Step 1: Calculate the number of moles of gas produced at STP. The molar volume of a gas at STP is 22.4 L/mol. Therefore, the number of moles of gas produced at STP is: n(gas) = V(gas) / molar volume n(gas) = 112 mL * (1 L / 1000 mL) / 22.4 L/mol n(gas) = 0.005 moles Step 2: Calculate the number of moles of alcohol that reacted with CH3MgI. The chemical equation for the reaction is: ROH + CH3MgI --> ROH2MgI + CH4 From the balanced equation, we can see that 1 mole of ROH reacts with 1 mole of CH3MgI to produce 1 mole of gas. Therefore, the number of moles of alcohol that reacted with CH3MgI is equal to the number of moles of gas produced: n(ROH) = n(gas) n(ROH) = 0.005 moles Step 3: Calculate the molecular mass of the alcohol. The molecular mass of the alcohol is equal to the mass of the alcohol divided by the number of moles of alcohol: M(ROH) = m(ROH) / n(ROH) M(ROH) = 0.412 g / 0.005 moles M(ROH) = 82.4 g/mol Therefore, the molecular mass of the alcohol is 82.4 g/mol.