Magnesium and Berylium react with H2SO4 to produce MgSO4 + H2, but
Calcium, Strontium and Barium with Dilute H2SO4, is a little more complicated.

Is this what happens or what you'd say happens:

Calcium, Strontium and Barium Sulphates are thought to be insoluble, hence a layer of insoluble sulphate will form, causing the reaction to slow down or stop completely.

So, does these group 2 elements not react with Dilute H2SO4?

It would produce a white precipitate and H2 bubbles.
What is the equation for the reaction?

Thank you :smile:

Reply 32

Gaiaphage

Original post by logicmaryam

I just checked too, apparently both are right as ammonia solution can be supplied as ammonia or ammonium hydroxide

When you dissolve NH₃ in water to make NH_3(aq), you get this reaction:

NH₃ + H₂O -> NH₄⁺ + OH^-

So whilst ammonia is NH₃, ammonia solution is NH₄OH.

Reply 33

AngelaMckenzie

What colour change is seen when oxidising a key tone?
What does that addition of HNO3 show, like i understand why you add it first, that's because it gets rid of any carbonates etc. but why afterwards? what does that show?
How can you tell which have sulphates and which contain sodium?

Reply 34

username1560589

Original post by The Informant

Ask me any problems you might be having with AS Biology or Chemistry Units 1, 2 and 3

I'm not an AS student, but I'm curious, why is there no "5" option in the poll?

Reply 35

The Informant

Original post by morgan8002

I'm not an AS student, but I'm curious, why is there no "5" option in the poll?

My apologies, I was doubting that anyone would do maths, chem, bio, physics and further as well. I thought most people would be human and do 2-3

Reply 36

The Informant

Original post by AngelaMckenzie

Oxidation of alcohols:
The oxidising agent used is acidified potassium dichromate solution. In that current state, there are Cr⁶⁺ ions which makes the solution orange.
2^o alcohol + [O] --> Ketone
During the oxidation process, the Cr⁶⁺ is reduced to form Cr³⁺ and this means that the colour change is from orange to green. You cannot further oxidise a ketone, so the solution will remain green.

HNO_3(aq)
For the EMPA task 2, we added HNO₃ to show the presence of SO₄^2- ions. This is because BaSO_4(s) is insoluble in HNO_3(aq), and if it dissolves, then you know that it is not the SO₄^2- ion.

Sulfates:
The BaCl_2(aq) tests for the presence of sulfate ions, by producing a white precipitate.
You can't really show Na⁺ ions. Sodium is however used in the test for alcohols, adding sodium to alcohols will result in effervescence.

Hope that answers your questions.