An ionic compound contains a metal cation and a non-metal anion in a 1 : 1 ratio, and water of crystallisation. The compound can be represented as MN.xH2O, where x is the number of moles of water of crystallisation per mole of MN.
A sample of MN.xH2O was dissolved in distilled water to produce a colourless solution, with a concentration of about 0.5 mol dm−3. 2 cm3 of the resulting solution was transferred to each of two test tubes.
The following tests were carried out to identify the ions present.
Test 1
i)
Addition of a few drops of a solution of barium chloride to one of the test tubes gave a white precipitate.
Identify, by name or formula, two possible anions that would give this result.
(1)
ii)
Addition of 1 cm3 of dilute hydrochloric acid to the test tube in (a)(i) resulted in no further change.
Give the formula of the anion.
(1)
iii)
What is the charge on the cation?
(1)
|
☐ |
A |
+1 |
|
☐ |
B |
-1 |
|
☐ |
C |
+2 |
|
☐ |
D |
-2 |