Acid-Base calculation (urgent help needed!)?

Question

1.48 g of an organic acid reacts completely with 25.0 cm^3 of 1.20 mol/dm^3 of aqueous sodium hydroxide.
Which of the following is probably the organic acid?

a) CH3COOH
b) CH2(COOH)2
c) CH(COOH)3
d) C(COOH)4

I need urgent help. my teacher couldn't help me and I can't find anything in the internet. Please do help, and do explain.

Thanks.

Could anyone explain why its C?

Answer 1

For acid-base you have

gr-eq acid= gr-eq base =>

a(acid)* mole(acid)= a(base)* mole (base) where a(acid) and a(base) is the valency of the acid and base respectively.

mole (base)= M(base)* V(base) = 1.20* 0.025= 0.0300= 30 mmole
for NaOH a(base)=1
thus 1*30=30 mgr-eq base

For the different acids you have a(acid)= number of COOH groups.
and since mole acid=mass/MW

greqs acid= a(acid)* mass/MW

You use this to find for which acid the 1.48 g correspond to the same mgr-eqs as the base.

(a) 1*1.48/60= 0.0246= 25 mgr-eq acid < 30 thus it is not the one
(b) 2*1.48/104= 0.0284 = 28 mgr-eq acid < 30
(c) 3*1.48/148= 0.0300= 30 mgr-eq acid= mgr-eq base. therefore (c) could be it.
(d)4*1.48/192= 0.0308= 31 mgr-eq acid > 30 thus it is rejected

therefore (c) is the correct one. (d) is quite close but (c) is the one that meets perfectly the requirements.

Answer 2

Its quite simple, first convert your units to proper terms... Litres, Molarity (moles per litre). Once there calculate the number of moles of base you have, for every one mole of base you need one mole of acid to neutralize it. From that point (sample weight)/(number of moles)=Molecular Weight, the closest value should be the right answer. Also keep in mind that organic acids are weak and you may want to look up their Ka's.
As for the abundance of answers c and d in the world, they are approximately nil as there is not enough physical room for them to be created without the molecule falling apart entirely.

Answer 3

did you solve it finally?
i think that something is missing
i wonder how the others soved it...and found it was C
add a detail if you found that you said something wrong on the first place and i will try to help you back

Answer 4

C MY DEAR