lunax
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Which statement about pH is correct?

A. The pH of a weak base is independent of temperature.

B. At temperatures above 298 K, the pH of pure water is less than 7.

C. The pH of 2.0 mol dm nitric acid is approximately 0.30

D. The pH of 0.10 mol dm sulfuric acid is greater than that of 0.10 mol dm hydrochloric acid.

I put D but I can't find the markscheme so please let me know, if you know.

Thank You!
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Pigster
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(Original post by lunax)
Which statement about pH is correct?

A. The pH of a weak base is independent of temperature.

B. At temperatures above 298 K, the pH of pure water is less than 7.

C. The pH of 2.0 mol dm nitric acid is approximately 0.30

D. The pH of 0.10 mol dm sulfuric acid is greater than that of 0.10 mol dm hydrochloric acid.

I put D but I can't find the markscheme so please let me know, if you know.

Thank You!
Why do you think it is D?
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robbie1237
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(Original post by lunax)
Which statement about pH is correct?

A. The pH of a weak base is independent of temperature.

B. At temperatures above 298 K, the pH of pure water is less than 7.

C. The pH of 2.0 mol dm nitric acid is approximately 0.30

D. The pH of 0.10 mol dm sulfuric acid is greater than that of 0.10 mol dm hydrochloric acid.

I put D but I can't find the markscheme so please let me know, if you know.

Thank You!
sulfuric acid is diprotic so I don't think it can be D
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lunax
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(Original post by robbie1237)
sulfuric acid is diprotic so I don't think it can be D
yh i know that's why I initially thought it was D, seems I read the question wrong. For some reason I got confused and thought a higher pH meant more acidic, but obviously not lol. Bit of a face palm moment there. Pretty sure it's B now though, since pH does change with temperature and it can't be the other options.
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lunax
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(Original post by Pigster)
Why do you think it is D?
I thought it was D because sulfuric acid is diprotic so it would be more acidic, but I realise now the questions is asking for the one with the higher pH (so less acidic). I just got confused lol. But I think the answer is B now.
Last edited by lunax; 1 month ago
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deskochan
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A. The pH of a weak base is independent of temperature.
Dissociation of weak acid or base is mildly endothermic

B. At temperatures above 298 K, the pH of pure water is less than 7.
The formation of hydrogen ions (hydroxonium ions) and hydroxide ions from water is an endothermic process, increase temp, more H+ produced

C. The pH of 2.0 mol dm nitric acid is approximately 0.30
pH = -log (2)

D. The pH of 0.10 mol dm sulfuric acid is greater than that of 0.10 mol dm hydrochloric acid.

This statement implied sulfuric acid is less acidic than hydrochloric acid at the same molarity
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