The number of mole of HCl needed for the solution is 1.035×10¯³ mole
<h3>How to determine the pKa</h3>
We'll begin by calculating the pKa of the solution. This can be obtained as follow:
- Equilibrium constant (Ka) = 2.3×10¯⁵
- pKa =?
pKa = –Log Ka
pKa = –Log 2.3×10¯⁵
pKa = 4.64
<h3>How to determine the molarity of HCl </h3>
- pKa = 4.64
- pH = 6.5
- Molarity of salt [NaZ] = 0.5 M
- Molarity of HCl [HCl] =?
pH = pKa + Log[salt]/[acid]
6.5 = 4.64 + Log[0.5]/[HCl]
Collect like terms
6.5 – 4.64 = Log[0.5]/[HCl]
1.86 = Log[0.5]/[HCl]
Take the anti-log
0.5 / [HCl] = anti-log 1.86
0.5 / [HCl] = 72.44
Cross multiply
0.5 = [HCl] × 72.44
Divide both side by 72.44
[HCl] = 0.5 / 72.4
[HCl] = 0.0069 M
<h3>How to determine the mole of HCl </h3>
- Molarity of HCl = 0.0069 M
- Volume = 150 mL = 150 / 1000 = 0.15 L
Mole = Molarity x Volume
Mole of HCl = 0.0069 × 0.15
Mole of HCl = 1.035×10¯³ mole
<h3>Complete question</h3>
How many moles of HCl need to be added to 150.0 mL of 0.50 M NaZ to have a solution with a pH of 6.50? (Ka of HZ is 2.3 x 10 -5 .) Assume negligible volume of the HCl
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The answer is 33.2 moles of a solute is present in 4.00 L of an 8.30 M solution , Option A is correct .
<h3>
What is Molarity ?</h3>
Molarity is defined as the amount of solute (in moles)in per litre of solution.
It is also known as molar concentration of a solution , It is expressed in mol/l

We can rearrange this equation to get the number of moles:
n= M * V
The molarity of solution is 8.3 M and the volume given is 4 litres
the moles will be n = 8.30 * 4 = 33.2 moles
Therefore 33.2 moles of a solute is present in 4.00 L of an 8.30 M solution , Option A is correct .
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Bonjour,
it’s cobalt(III) sulfate
HNO3
Explanation:
hydrochloric acid (HCl), sulfuric acid (H 2start subscript, 2, end subscriptSO 4start subscript, 4, end subscript), nitric acid (HNO 3start
Answer:
Kc = [C2H5OH]/{[C2H4][H2O]}
[H2O] = [C2H5OH]/{[C2H4] x Kc}
[H2O] = 1.69/(0.015 x 9.0 x 10^3) = 0.013 M
Explanation:
Kc is the equilibrium constant, it is egal to the product of the equilibrium concentration of the product dived by the product of the equilibrium concentration of the reactants.
with that formula and what is given, male the equilibrium concentration of H2O the subject of the formula and calculate its concentration by substituting given values.