Answer:- HBr is limiting reactant.
Solution:- The given balanced equation is:

From this equation, There is 2:6 mol or 1:3 mol ratio between Al and HBr. Since we have 8 moles of each, HBr is the limiting reactant as we need 3 moles of HBr for each mol of Al.
The calculations could be shown as:

= 24 mol HBr
From calculations, 24 moles of HBr are required to react completely with 8 moles of Al but only 8 moles of it are available. It clearly indicates, HBr is limiting reactant.
Answer:
None of the options are correct.
Explanation:
1) when the temperature of the solution is increased the solubility of the gas in the liquid decreases , hence option 1 is incorrect.
2)The heat released by the dissolution of an ionic compound in water is heat of hydration of the compound and is independent of the initial temperature of the solution.
3) The solubility of a liquid in water is not affected significantly by the pressure changes in the system as gases only have a significant cahne in solubility with change in pressure.
Answer:
Protons
Explanation:
Protons are the subatomic particle that determines the identity of an element.
Answer: The correct option is 3.
Explanation: We are given a compound which is made up of iron and oxygen only. The ratio of the two are given as:

This means that, number of iron ions are 2
Number of oxide ions are 3
From the above information, the formula becomes : 
The valency of iron = 3
Valency of oxide = 2
This compound is named as iron (III) oxide.
Hence, the correct option is 3