The Student Room Group

Chemo question - White solid

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Surely nitrogen and hydrogen is produced? But the mark scheme said it was "B"
Original post by Hazel99
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Surely nitrogen and hydrogen is produced? But the mark scheme said it was "B"

The standard thermal decomposition produces Oxygen and potassium nitrite.
(edited 7 years ago)
Reply 2
What do the other answers produce?
Original post by Hazel99
What do the other answers produce?


Strontium Nitrate produces Strontium Oxide, Nitrogen Dioxide and Oxygen
Calcium Oxide does not decompose. It's too stable.
Lithium nitrate decomposes into Lithium Oxide, Nitrogen Dioxide and Oxygen.
Reply 4
Original post by Kvothe the Arcane
Strontium Nitrate produces Strontium Oxide, Nitrogen Dioxide and Oxygen
Calcium Oxide does not decompose. It's too stable.
Lithium nitrate decomposes into Lithium Oxide, Nitrogen Dioxide and Oxygen.


Why does potassium nitrate produce only oxygen where as lithium nitrate produces nitrogen dioxide??
Original post by Hazel99
Why does potassium nitrate produce only oxygen where as lithium nitrate produces nitrogen dioxide??


I don't know why exactly but the rule is that:

Group 1 (except lithium) decompose to the nitrite and oxygen

Group II (and lithium) decompose to the oxide, nitrogen dioxide and oxygen.

@alow might be able to shed more light.

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