Why is it necessary to use acetic acid and not `H_2SO_4` for acidification of sodium extract for testing sulphur using lead acetate test?

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

Why is it not advisable to dissolve KMnO_(4) in conc. H_(2) SO_(4)

Why is concentrated sulphuric acid not used as a drying agent in the preparation of ammonia?

You are given benzene,conc H_2 SO_4 and NaOH. Write the equations for the prepartion of phenol using these reagents.

In the contact process of manufacturing of H_2SO_4 , the catalyst used is:

When a white crystalline compound 'X' is heated with K_(2)Cr_(2)O_(7) and concentrated H_(2)SO_(4) a red dish brown gas 'A' is evolved. On passing 'A' into caustic soda solution, a yellow coloured solution of 'B' is obtained. Neutralising the solution 'B' with acetic acid and on subsequent addition of lead acetate a yellow precipitate C is obtained. When 'X' is heated with NaOH a colourless gas is evolved and on passing this a gas into K_(2)HgI_(4) (Nessler's reagent) solution a reddish brown precipitate D is formed. Identify '(A), (B), (C), (D) and X. Write equations for the reactions involved.

Why is Ka_2 less than Ka_1 for H_2SO_4 in water.?

For the detection of sulphur, using lead acetate solution, the fusion extract is acidified with