IIT JEE , AIEEE Forum - Chemistry , Physical Chemistry

vercitty

1) An exp requires 100 cm3 of 20% H2SO4, densitty 1.14 g/cm3. How much conc acis, of density 1.84 g/cm3 and containing 98% H2SO4 by weight, must be diluted with water to prepare 100cm3 acid of the required solution ?

vercitty

Please reply. I have the answer. I'll tell you if it is wrong or correct. But i didnt get the logic.

I suck in chem and i am trying to get better in it.

sahilmadaan12

its very easy

i think u shud the equivalent weight method

just wait for 5 min....... m solving

sahilmadaan12

m getting ans as 12.644ml..............m i correct

vercitty

yep, u r lol. How do u do it?

vercitty

It would be good if u tell the steps bro. Your 5 minutes can help me.

sahilmadaan12

see first of find the molarity from the percentage
by formula M= (10 * % * d)/m
where m =molar mass of sulfuric acid
M= molarity
d= = density of sol
% = percentage of solution

now use M1*V1 = M2* V2

(10 * 98 * 1.84*V)/ 98 = [10 * 20 * 1.14 *100(ml)]/98
find V in above

sahilmadaan12

i expect u to learn this M= (10 * % * d)/m formula if u dont know already..........as it is used very frequently in competitions

vercitty

Thanks bro. That was easy to understand.
And here is the sol i have :

Mass of H2SO4 per ml of 20% acid = .200*1.14 = .228 g/ml
"""""""""""""""""""""""""""""""98% acid = .980*1.84=1.8 g.ml
So, 100*.228 = V*1.80
v=12.7 ml approx

What happened in the above solution?

vercitty

I gave u 15 votes lol.

sahilmadaan12

see in the above ans....question is done by pure definition....so both will ultimetly reach the same thing.........i wud suggest the equivalence method as it is more general

vercitty

awesome

sahilmadaan12

thanks

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