Home
Class 11
CHEMISTRY
Why is nitric acid added to sodium extra...

Why is nitric acid added to sodium extract before adding silver nitrate for testing halogens?

Text Solution

Verified by Experts

Problem can arise in case the organic compound which also contains nitrogen and sulphur in addition to halogens. Both will form `NaCN` and `Na_(2)S` on fusion with sodium metal and will react with silver nitrate solution to give precipitates.
`NaCN+AgNO_(3) rarr underset("White ppt.")(AgCN)+NaNO_(3)`
`Na_(2)S+2AgNO_(3) rarr underset("Black ppt.")(Ag_(2)S)+2NaNO_(3)`
These precipitates will interfere with the precipitate of silver of silver halide formed due to halogens. Nitric acid is added to destroy both these compounds to form volatile gases.
`NaCN+HNO_(3) rarr NaNO_(3)+HCN uarr`
`Na_(2)S+2HNO_(3) rarr 2NaNO_(3)+H_(2)S uarr`
Promotional Banner

Similar Questions

Explore conceptually related problems

The function of boiling the sodium extract with concentrated nitric acid before testing halogens is

When dilute nitric acid is added to copper turning, the gas evolved is

(a) how is a mixture of two organic compounds separated, which have different solubilities in the ame solvent? (b) How is an organic liquid purified which decomposes below its boiling point? (c) Why is sodium extract boiled with HNO_3 before testing for halogens? (d) What type of organic compounds cannot be estimated by Kjeldahl's method? (e). What does blood-red colouration during Lassaigne's test indicate? (f). What happens when AgNO_3 solumtion is added to bromo methane?

Write the balanced chemical equations for the following : (a) Pb_(3)O_(4) is treated with nitric acid. (b) Zinc oxide is treated with excess of sodium hydroxide solution. (c) Dilute nitric acid is slowly reacted with metallic tin. (d) Gold is dissolved in aqua regia. (e) Iron reacts with cold dilute nitric acid. (f) Sodium thiosulphate is added slowly to silver nitrate. (g) Heating of ZnCI_(2).2H_(2)O .

Why is sodium carbonate extract acidified before perfoming the confirmatory tests for anions?

Why is it necessary to use acetic acid and not suplhuric acid for the acidification of sodium extract for testing suplhur by lead acetate test?

What happens when nitric acid is added to egg shell ?

Freshly prepared solution of sodium nitroprusside is added to the sodium extract. Appearance of a deep violet colour indicates the presence of

Why sodium carbonate extract is used for testing acid radicals?

Sodium extract is heated with con. HNO_(3) before testing for halogens because