Practice Questions

Question 1

A white solid was thought to be barium carbonate. A student suggested that the presence of
the carbonate ion could be tested for by adding a small amount of sulfuric acid.why is this wrong

Answer 1

Because usually to test for carbonate ions we add acid so that co2 will be produced however in this case barium sulfate would be produce which is very insoluble and may cause it to appear that the carbonate is not reacting

Question 2

Explain how the trend in reactivity for group 2 elements is determined by their electron configuration

Answer 2

Outer electrons is further from nucleus
There is more shielding from shells of inner electrons
So it takes less energy to remove electron so reactivity increases down group(first ionisation energy decreases down group)

Question 3

The solution of X was dissolved in deionized water, acidified with HCl, and then barium chloride (BaCl₂) solution was added.
A white precipitate formed, indicating the presence of..

Answer 3

Sulfate ions as barium chloride will only form white precipitate if sulfate ions are present

Question 4

Why might the experimental volume be Dif from theoretical volume assuming no gas escaped and measurements are made accurately

Answer 4

Incomplete reaction

Question 5

During flame test why do we dip nichrome into hcl

Answer 5

To remove residue if any other previous sample

Question 6

Explain the trend in thermal stability of group two nitrates down the group

Answer 6

Become more stable down group as atomic radius increases less polarising effect on carbonate ions so o-n bond less weak

Question 7

Aqueous sodium carbonate and aqueous sodium sulfate are both colourless solutions.
Give the reagent and the observation to show the presence of carbonate ions.

Answer 7

Strong acid , we get effluence and fizzing