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Answer:
plzz mark brainliast:
Explanation:
clue: The reaction has a single reactant.
The minimum volume of 0.2M sodium sulfide that will precipitate out aluminum from 50.0 mL, 0.25 M aluminum nitrate would be 0.094 L or 94 mL
<h3>Stoichiometric calculation</h3>
From the equation of the reaction:

Mole ratio of Na2S and Al(NO3)3 = 3:2
Mole of 50.0 mL, 0.25 M Al(NO3)3 = 50/1000 x 0.25
= 0.0125 mole
Equivalent mole of Na2S = 3/2 x 0.0125
= 0.0188 mole
Volume of 0.2M, 0.0188 mole Na2S = 0.0188/0.2
= 0.094 L or 94 mL
More on stoichiometric calculations can be found here: brainly.com/question/8062886
Answer:
The hydrogen ion concentration of the substance is 3.16*10⁻⁵ M
Explanation:
pH is a parameter used to measure the degree of acidity or alkalinity of a substance. The pH is calculated as the negative logarithm (base 10) of the concentration of hydronium ions [H₃O⁺] or hydrogen ions [H⁺].
pH= - log [H₃O⁺]= - log [H⁺]
Values on the pH scale range from 0 to 14, where pH equal to 7 is neutral, below 7 is acidic and above 7 is basic.
In this case, pH= 4.5
So:
4.5= - log [H⁺]
Solving:
[ H⁺]= 10⁻⁴ ⁵
[H⁺]= 3.16*10⁻⁵ M
The hydrogen ion concentration of the substance is 3.16*10⁻⁵ M