DP Chemistry (last assessment 2024)

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Question 20N.3.sl.TZ0.2g

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Date November 2020 Marks available [Maximum mark: 1] Reference code 20N.3.sl.TZ0.2g
Level sl Paper 3 Time zone TZ0
Command term Suggest Question number g Adapted from N/A
g.
[Maximum mark: 1]
20N.3.sl.TZ0.2g

An investigation was carried out to determine the effect of chain length of the alcohol on the equilibrium constant, Kc, for the reversible reaction:

ROH+CH3COOHH+aq CH3COOR+H2O

The reactants, products and the catalyst form a homogeneous mixture.

Fixed volumes of each alcohol, the ethanoic acid and the sulfuric acid catalyst were placed in sealed conical flasks.

At equilibrium, the flasks were placed in an ice bath, and samples of each flask titrated with NaOH(aq) to determine the ethanoic acid concentration present in the equilibrium mixture.

The following processed results were obtained.

© International Baccalaureate Organization 2020

(g)

Suggest a risk of using sulfuric acid as the catalyst.

[1]

Markscheme

corrosive/burns/irritant/strong oxidizing agent/carcinogenic
OR
disposal is an environmental issue
OR
causes other side reactions/dehydration/decomposition ✔


Do not accept just “risk of accidents” OR “health risks” OR “hazardous”.

Examiners report

Most students received a mark for this question base on specific hazards. Very few students related disposal to environmental issues which isn't surprising as this is often missed in the Internal Assessment. Weaker students provided vague answers related to health issues which did not receive a mark. Some students misunderstood the question.