Answer:
The concentration of KOH is 0.186 M
Explanation:
First things first, we need too write out the balanced equation between HBr and KOH.
This is given as;
KOH (aq) + HBr (aq) → KBr (aq) + H2O (l)
From the reaction above, we can tell that it takes 1 mole of KOH to react with 1 mole of HBr.
We use the acid base formular in calculating unknown concentrations. This is given as;

where;
Ca = Concentration of acid
Va = Volume of acid
Cb = Concentration of base
Vb = Volume of base
na = Number of moles of acid
nb = Number of moles of base
KOH is the base and HBr is acid.
Hence;
Ca = 0.225
Va = 35
Cb = ?
Vb = 42.3
na = 1
nb = 1
Making Cb subject of formular we have;

Cb = (0.225 * 35 * 1) / (42.3 * 1)
Cb = 0.186 M
Sodium is not a macromolecule hence it does not contain any calories.
<h3>Does sodium contain calories?</h3>
The term calorie is a unit of energy. We often us the term to describe the amount of energy that is contained in each kind of food. The higher the calories, the greater the energy that the food contains.
Calories can only be contained by macromolecules such as proteins, carbohydrates, fats etc. Sodium is not a macromolecule hence it does not contain any calories at all hence the classmate is wrong.
Learn kore about calories:brainly.com/question/22374134
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Explanation:
Regulate body temperature in the extremes of space. maybe