chemistry amount of substance aqa alevel question

Which amount of sodium hydroxide would react exactly with 7.5 g of a diprotic acid, H2A (Mr = 150)?
A 50 cm3 of 0.05 mol dm–3 NaOH(aq)
B 100 cm3 of 0.50 mol dm–3 NaOH(aq)
C 100 cm3 of 1.0 mol dm–3 NaOH(aq)
D 100 cm3 of 2.0 mol dm–3 NaOH(aq)

answer is c

Have you tried writing an equation for the reaction of NaOH and H2A?

nope, i didn't know u had to do that in order to answer the q. now that u mentioned it, i dont know how to write it though

A diprotic acid is one that donates 2 protons (H+ ions) to the base. As TypicalNerd mentioned above, you can write this down as H2A (as you do not know what type of acid it is).

Now remember, acid + base = salt + water

So, NaOH + H2A => NaA + H2O

Can you try balancing this equation now?

A diprotic acid is one that donates 2 protons (H+ ions) to the base. As TypicalNerd mentioned above, you can write this down as H2A (as you do not know what type of acid it is).

Now remember, acid + base = salt + water

So, NaOH + H2A => NaA + H2O

Can you try balancing this equation now?