im not sure which one to answer, and i can hardly see the text.
As I understand from your question, we should synthesize nickel sulfate first from nickel (II) oxide and sulfuric acid and second from nickel carbonate and sulfuric acid.
The chemical reactions will look like this:
NiO (s) + H₂SO₄ (aq) → NiSO₄ (aq) + H₂O (l)
NiCO₃ (aq)* + H₂SO₄ → NiSO₄ (aq) + H₂CO₃ (aq)
but carbonic acid will decompose to carbon dioxide and water
H₂CO₃ (aq) → CO₂ (g) + H₂O (l)
(*) NiCO₃ has a poor solubility in water, but enough to start the reaction.
For metals (lithium) reactivity increases down a group and from right to left across a period. So lithium is not that reactive. I think ♀️
Answer: A) True
Explanation: The difference in energy levels in an atom is responsible for the emission of photons. Emitted photons have different energies because energy levels are discrete. The energy of a photon gives information about its frequency and subsequently, its colour.
As the two gases (Hydrogen & Helium) are distinctively different gases with different discrete energy levels in their atoms, it is logical that the frequency and colour of the emitted photons from their respective atoms would be different.
The answers is C because they are pulling with different amount of forces opposite ways and there is more force towards the left.
