(a) Give the reason in each case why it is necessary to:

(i) moisten a piece of litmus paper used in testing for the acidity or alkalinity of a gas.

(i) acidify the test solution with dilute hydrochloric acid in the confirmatory test for SO\(_4^2\)

 

(b)(i) List two gases that must not be prepared in the open laboratory

(ii) Mention one precaution that should be taken in the laboratory to prevent excessive inhalation of these gases during their preparation.

(iii) State one use of each of the following pieces of apparatus in the laboratory. I. Wash bottle II. Tripod stand

(c) State what would be observed when:

(i) Pb(NO\(_3\))\(_2\) is needed

(ii) concentrated HCI is added to MnO\(_2\)