Moles of calcium metal used = 100/40.1=2.5
Moles of HBr need to react = 5 moles
As the molar ratio is 1 is to 2 among them
so
Moles=molarity x volume
5=2.25 x volume
volume=2.22 litres of HBr required for this reaction
ANSWER IS 2.22 LITRES
Both the sat water ice cubes would freeze due to the temperature of the freezer.
The question is incomplete, complete question is:
Study this chemical reaction:

Then, write balanced half-reactions describing the oxidation and reduction that happen in this reaction.
Oxidation:
Reduction:
Answer:
Oxidation taking place in given reaction :

Reduction taking place in given reaction;
Explanation:
Redox reaction is defined as the reaction in which oxidation and reduction reaction occur side by side.
Oxidation reaction is defined as the chemical reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.
Reduction reaction is defined as the chemical reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.


In the given reaction, iron(II) ions are getting reduced and zinc metal is getting oxidized to zinc(II) ions.
Oxidation :

Reduction ;
Answer: The balance of the reaction shifts toward the endothermic reaction.
Explanation:
An ENDOTHERMIC REACTION requires input of HEAT ENERGY to drive it FORWARD from reactants, unto completion of products.
So, on increasing the temperature (available heat) the REVERSIBLE REACTION favors the shifts towards the endothermic reaction