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Specialty Chemistry Forums => Citizen Chemist => Topic started by: 19kevin87 on June 14, 2010, 11:45:03 PM

Title: How much Vol of 48.5% of NaOH needed to neutralize 21mL of 4.7% H2SO4
Post by: 19kevin87 on June 14, 2010, 11:45:03 PM

I've calculated and my answer is 1.66 mL.
But I'm not sure bout the ans plus my working is too complicated, can you show me how u get the ans?
Correct me if I'm wrong.
Thanks! :)
my version:
1) to change % to concentration
   For H2SO4: 4.74*10/MW_H2SO4 = 0.48 mol L^-1
   For NaOH: 48.5*10/MW_NaOH = 12.13 mol L^-1
2) 0.48mol of 21mL H2SO4 is eq to 0.01008 mol
3) since acid to alkali ratio is 1:2, therefore moles of NaOH needed is 0.02016 mol
4) therefore volume needed for 48.5% NaOH is
   0.02016*1000/12.13 = 1.66 mL

Thanks again!

Title: Re: How much Vol of 48.5% of NaOH needed to neutralize 21mL of 4.7% H2SO4
Post by: AWK on June 15, 2010, 01:51:11 AM

Densities of both solutions are needed

Title: Re: How much Vol of 48.5% of NaOH needed to neutralize 21mL of 4.7% H2SO4
Post by: 19kevin87 on June 15, 2010, 04:30:39 AM

Quote from: AWK on June 15, 2010, 01:51:11 AM

Densities of both solutions are needed

Ya, from the formula, the densities are needed.. since both sulphuric acid and caustic soda have density around 1gcm^-3, i treat it as 1

Title: Re: How much Vol of 48.5% of NaOH needed to neutralize 21mL of 4.7% H2SO4
Post by: Borek on June 15, 2010, 05:42:18 AM

Quote from: 19kevin87 on June 15, 2010, 04:30:39 AM

since both sulphuric acid and caustic soda have density around 1gcm^-3, i treat it as 1

That's true only for diluted solutions, one of the solutions in question have density around 1.5 g/mL.