Credit will be given for strict adherence to the instructions, for observations precisely recorded, and for accurate inferences. All tests, observations, and inferences must be clearly entered in your answer book, in ink, at the time they are made.
C and D are two aqueous solutions. Carry out the following exercises on C and D. Record your observations and identify any gas(es) evolved. State the conclusion you draw from the result of each test.
(a)(i) To about 2 cm\(^3\) portion of C, add NaOH\(_{(aq)}\) In drops until in excess. Warm the mixture
(ii) To another 2 cm\(^3\) portion of C, add HCl\(_{(aq)}\) followed by BaCl\(_{2(aq)}\)
(b)(i) (ii) To another 2 cm\(^3\) portion of D, add add NH\(_{3(aq)}\) drops and then in excess.
(ii) To about 2 cm\(^3\) portion of D, add AgNO\(_{3(aq)}\) followed by HNO\(_{3(aq)}\)
Explanation
| TEST | OBSERVATION | INFERENCE |
|
(a)(i) C + NaOH\(_{(aq)}\) + warm
(ii) C + HCl\(_{(aq)}\) + BaCl\(_{2(aq)}\)
(b)(i) D + NH\(_{3(aq)}\)
(ii) D + AgNO\(_{3(aq)}\) + HNO\(^{3(aq)}\) |
No visible reaction/no pot A colourless gas with pungent/choking/irritating smell evolved. Gas turned damp red litmus blue/formed white fumes with conc HCl vapour
No visible reaction while ppt formed Reddish - brown/brown ppt ppt insoluble
White ppt ppt insoluble |
Gas is NH\(_3\) from NH\(_4^+\)
SO\(_4^{2-}\) present Fe\(^{3+}\) present
Cl\(^-\) or CO\(_3^{2-}\) Cl\(^-\) present |