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Acids, bases and salt preparations

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Question 15

Solutions of barium chloride and sodium sulfate react together to form the insoluble salt barium sulfate.

a.

A student wrote this plan to prepare a pure dry sample of barium sulfate:

  • step 1: pour some barium chloride solution into a beaker
  • step 2: add sodium sulfate solution until the reaction is complete
  • step 3: filter the mixture
  • step 4: heat the filtrate to evaporate some of the water
  • step 5: cool the filtrate and remove the crystals

(i) How will the student know when the reaction in step 2 is complete?

[1]
b.

(ii) Which compound could the student use in this preparation instead of sodium sulfate?

  • A barium hydroxide
  • B hydrochloric acid
  • C sodium hydroxide
  • D sulfuric acid
[1]
c.

(iii) State why the student should not have included steps 4 and 5 in his plan.

[1]
d.

(iv) Suggest replacement steps to obtain a pure dry sample of barium sulfate.

  • step 4:
  • step 5:
[2]
e.

(v) Barium carbonate cannot be used instead of barium chloride in this preparation. This is because barium carbonate:

  • A contains covalent bonding
  • B has a high relative formula mass
  • C is insoluble in water
  • D is toxic
[1]
f.

The equation for the reaction in the student's plan is:

BaCl2(aq)+Na2SO4(aq)→BaSO4(s)+2NaCl(aq) \text{BaCl}_2(\text{aq}) + \text{Na}_2\text{SO}_4(\text{aq}) \rightarrow \text{BaSO}_4(\text{s}) + 2\text{NaCl}(\text{aq}) BaCl2​(aq)+Na2​SO4​(aq)→BaSO4​(s)+2NaCl(aq)

(i) Deduce the amount of each reactant needed to form 0.120 mol of barium sulfate.

  • BaCl2\text{BaCl}_2BaCl2​: ___________ mol
  • Na2SO4\text{Na}_2\text{SO}_4Na2​SO4​: ___________ mol
[1]
g.

(ii) What volume of 0.400 mol/dm3 barium chloride solution is needed to form 0.120 mol of barium sulfate?

[2]

Acids, bases and salt preparations Questions

  1. IGCSE
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  3. /Acids, bases and salt preparations