DP Chemistry (last assessment 2024)

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Question 19M.3.hl.TZ1.17b(iii)

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.3.hl.TZ1.17b(iii)
Level hl Paper 3 Time zone TZ1
Command term Outline Question number b(iii) Adapted from N/A
b(iii).
[Maximum mark: 1]
19M.3.hl.TZ1.17b(iii)

E10 is composed of 10% ethanol and 90% normal unleaded fuel.

(b(iii))

Outline why aqueous ethanol, rather than pure ethanol, is used in a DEFC.

[1]

Markscheme

Any one of:
water is a reactant/allows the cell to operate at a higher concentration of protons/H+ ions
OR
water is a stronger electrolyte and thus produces higher electric current    [✔]

less dangerous/flammable    [✔]

Examiners report

Few candidates could outline why aqueous ethanol is used in a DEFC.

Syllabus sections