the answer should be D, maybe answer key is wrong

C is correct.

LockB, you need to write the balanced equation to realise that the mole ratio of potassium hydroxide to sulfuric acid is 2 : 1 (we need this for the computations).

when i wrote the chemical equation out, i noticed that there is 2H+ for both H2SO4 and KOH hence i thought the concentration required for H2SO4 will be the same as KOH (1.0mol/dm^3)

why is this wrong tho

Here we must be careful.

1. I know that there are two hydrogen ions for every H2SO4.

2. I also know that every hydrogen ion reacts with exactly one hydroxide ion to allow the neutralisation to proceed (meaning to say that two hydrogen ions require two hydroxide ions for neutralisation).

3. However, the two hydrogen ions come in the form of one molecule of H2SO4 while the two hydroxide ions come in the form of two separate molecules of KOH.

4. This means that one molecule of H2SO4 reacts with two molecules of KOH.

5. This also means that one mole of H2SO4 reacts with two moles of KOH.

6. It is worth noting, in your case, that the hydrogen ion to hydroxide ion ratio is 1 : 1 (leading to why you felt that the mole ratio should be 1 : 1).

7. However, in actual reality, the reactants come in the form of H2SO4 molecules and KOH molecules rather than random hydrogen ions and hydroxide ions, so the actual mole ratio should be based on actual molecules rather than the ions themselves,.