Methanesulfonic acid has the structure shown. [Figure showing structure of methanesulfonic acid] H O | || H—C—S—O | || | H O H

1. (a)Write the molecular formula for methanesulfonic acid.[1]
2. (b)Methanesulfonic acid is a stronger acid than ethanoic acid. Explain the meaning of this statement.[1]
3. (c)What is the difference between an aqueous acid and an aqueous alkali, in terms of the ions present?[2]
4. (d)What is the mass of methanesulfonic acid needed to make 150 cm³ of a 0.150 mol/dm³ solution? mass ..................................................... g[3]
5. (e)In a titration, 0.00150 moles of NaOH is exactly neutralised by 0.175 mol/dm³ methanesulfonic acid. One mole of sodium hydroxide reacts with one mole of methanesulfonic acid. Calculate the volume, in cm³, of aqueous methanesulfonic acid needed in this titration. volume ..................................................... cm³[1]
6. (f)(i)Methanesulfonic acid reacts with magnesium to make a salt and a gas. Name the gas made in this reaction.[1]
7. (f)(ii)The formula of the anion in the salt is CH3SO3⁻. Write the formula of the salt formed.[1]

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