Study of Compounds - Nitric Acid — Chemistry STD 10 — Question

Why is it necessary to add acid to water before proceeding with electrolysis of water?

Brown ring disappear if the test tube is disturbed.

(a) What chemical compounds are required for the laboratory preparation of nitric acid?
(b) Why does pure nitric acid take on a yellowish-brown colour when exposed to light?

Solution A is a strong acid.
Solution B is a weak acid.
Solution C is a strong alkali.
(i) Which solution contains solute molecules in addition to water molecules?
(ii) Which solution will give a gelatinous white precipitate with zinc sulphate solution? The precipitate disappears when an excess of the solution is added.
(iii) Which solution could be a solution of glacial acetic acid?
(iv) Give an example of a solution which is a weak alkali.

From the following list of substances, choose one substance in each case which matches the description given below:
Ammonium nitrate, Calcium hydrogen carbonate, copper carbonate, lead nitrate, potassium nitrate, sodium carbonate, sodium hydrogen carbonate, zinc carbonate.
(a) A Substance that gives off only oxygen when heated.
(b) A Substance which on heating decomposes into dinitrogen oxide (nitrous oxide) and steam.
(c) A Substance that gives off oxygen and nitrogen dioxide when heated.
(d) A Substance which on heating leaves a yellow residue.

(a) Why is hydrogen ion called a proton? Explain.
(b) An atom of fluorine may be written as ₉F¹⁹. Using dot diagram to show electrons in the outermost shell, show how a molecule of fluorine (F₂) is formed? What is the name given to this kind of bonding?

Give two tests of the following:
Water vapour

Write the equation for the preparation of carbon tetrachloride from methane.

In using sulphuric acid to prepare other acids, as mentioned above, which property of sulphuric acid is used ?