[Shordaay]

1. solution A contains 6.4 g/ dm cube of a mixture of NaOH and Na2SO4. solution B contain 4.9 g/dm cube H2SO4. only the NaOH in the mixture reacts with the H2SO4 and from titration it was found that:

25.0cm cube of solution A= 23.95 of H2SO4
according to the equation:
H2SO4 (aq) + 2 NaOH (aq) = Na2SO4 (aq) + 2H2O (L)
find the percentage composition by mass of the mixture (ans. 59.88% NaOH; 40.12% Na2SO4)

2. solution C contains 11/37 g/dm cube of an acid HX. solution D contains 4.48 g/ dm cube potassium hydroxide solution. on titration it was found that:

25.0 cm cube of solution D= 22.50 cm cube of solution C

use these titrations results to find the relative atomic mass of X and hence its identity.the equation for the reaction is:
KOH (aq) + HC (aq) = KX (aq) + H2O (L)

[Zishi]

(Original post by Shordaay)
1. solution A contains 6.4 g/ dm cube of a mixture of NaOH and Na2SO4. solution B contain 4.9 g/dm cube H2SO4. only the NaOH in the mixture reacts with the H2SO4 and from titration it was found that:

25.0cm cube of solution A= 23.95 of H2SO4
according to the equation:
H2SO4 (aq) + 2 NaOH (aq) = Na2SO4 (aq) + 2H2O (L)
find the percentage composition by mass of the mixture (ans. 59.88% NaOH; 40.12% Na2SO4)

2. solution C contains 11/37 g/dm cube of an acid HX. solution D contains 4.48 g/ dm cube potassium hydroxide solution. on titration it was found that:

25.0 cm cube of solution D= 22.50 cm cube of solution C

use these titrations results to find the relative atomic mass of X and hence its identity.the equation for the reaction is:
KOH (aq) + HC (aq) = KX (aq) + H2O (L)

1) You've been given the reaction equation, so first find the moles of sulphuric acid used by using the formula . It's actually just cancelling units instead of a real formula. You need to convert concentration in gdm^-3 to concentration in moldm^-3. Using the molar equation, you should be able to find moles of NaOH reacted and so it's concentration in the given volume. Do you get how to do after that?

2) You should be able to do it now using some of the information I provided in 1. What problem are you facing in it?

[Shordaay]

thank you i understood and did it

[Golden Boy]

(Original post by Shordaay)
thank you i understood and did it

I have no clue on how to find X in question 2. Can you show me how?

[Golden Boy]

(Original post by Golden Boy)
I have no clue on how to find X in question 2. Can you show me how?

any change my answer to X = 2.34. But there's no atom with the Relative Atomic Mass of 2.34...

Are you sure that the solution C has the concentration of 11/37 g/dm^3 ?

[Shordaay]

sorry that must have been a mistake.... 11.37 g dm^3

[Golden Boy]

(Original post by Shordaay)
sorry that must have been a mistake.... 11.37 g dm^3

I see... thanks for replying.

[Golden Boy]

I got X as Iodine.