The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

Help!! A2 Titration Question

Hi! Please could you help me with this question.

A 0.80 g sample of brass was dissolved in nitric acid to produce a mixture of copper(II) nitrate and zinc nitrate. Excess potassium iodide was added and the iodine produced reacted with 35.4 cm^3 of 0.200 mol dm^-3 sodium thiosulphate solution. Determine the composition of brass as % copper and zinc.

Thanks! :smile:
Original post by champion1
Hi! Please could you help me with this question.

A 0.80 g sample of brass was dissolved in nitric acid to produce a mixture of copper(II) nitrate and zinc nitrate. Excess potassium iodide was added and the iodine produced reacted with 35.4 cm^3 of 0.200 mol dm^-3 sodium thiosulphate solution. Determine the composition of brass as % copper and zinc.

Thanks! :smile:


.. and your ideas are?
Reply 2
Avatar for champion1
champion1
OP
3
Original post by charco
.. and your ideas are?


I think since brass hass copper and zinc, they react with the nitric acid as follows.

Cu + 4HNO3 --> Cu(NO3)2 + 2NO2 + 2H2O
Zn + 2HNO3 --> Zn(NO3)2 + H2

And then I'm stuck from there!
Reply 3
Avatar for GDN
GDN
1
You need to know 2 further reactions 1. the reaction between Cu2+ and I- and 2 the reaction between iodine and thiosulphate After that its a normal titration calculation
(edited 9 years ago)

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you