Quelpr
3 marksIdentification of Cations and Anions

CAPE Chemistry Unit 1 · 2017 · Question 1(a)

Substance R is a mixture of two simple salts, one containing the sodium cation, Na⁺. You are asked to carry out tests on Substance R, adding reagents gradually with gentle shaking until no further change. You need to record deductions alongside observations in Table 1, including details of color changes, precipitates, names of evolved gases, and tests used to identify each gas.

Heat strongly a small quantity of R and allow to cool. Test for gas evolved. Observe residue.

This question uses a figure or table from the paper — you'll see it when you practise.

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 1(b)To a small sample of R, add dilute HCl and warm.[2 marks]
  2. 1(c)To another small sample of R, add concentrated H₂SO₄ and heat carefully.[2 marks]
  3. 1(d)(i)Dissolve a spatula-full of R in minimum volume of dilute hydrochloric acid (warming if needed). Dilute with water to half of a test tube. Divide the solution…[3 marks]
  4. 1(d)(ii)To the second sample of the solution add AgNO₃(aq).[1 mark]
  5. 1(e)Write the chemical formula for the other product formed with water when excess NaOH(aq) is added in (d) (i).[1 mark]

More practice: the rest of this paper · more Identification of Cations and Anions questions · all CAPE Chemistry Unit 1 past papers