CHM 116 CBT Questions.

1. When the solution of a sample was heated and passed with hydrogen sulphide gas. A solid black compound formed. The chemical reaction involved is represented by one of the following

            A. Pb + S2-                      PbS                        B. Fe +  S2-                         FeS

            *C. Cu + S2-                    CuS                       D. Cd + S2-                            CdS

2. If a brown precipitate readily dissolved in HCl and added with KCN to give a blood red colour, then the cation present is

            A. Cr3+        B. Fe2+    *C. Fe3+          D. Cd3+