pH is offered to define acidity or basicity that substances. Its variety varies indigenous 0 come 14. That is characterized as negative logarithmof hydrogen ion concentration.
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The expression for pH is discussed below.
Dissociation reaction the KCN is together follows:
Cyanide ions thus developed can react v water to type HCN and
The relation between , and also is expressed by adhering to relation:
is the ionic product consistent of water.
is the dissociation constant of base.
is the dissociation constant of acid.
The value of is
The worth of is
Substitute these values in equation (2).
Solve because that ,
The expression because that the HCN is together follows:
Consider x to be adjust in equilibrium concentration. Therefore, equilibrium concentrationof
Solving for x,
Therefore concentration of hydroxide ion is 0.002 M.
The expression to calculate pOH is together follows:
Substitute 0.002 M for
The relation between pH and also pOH is together follows:
pH + pOH = 14 …… (5)
Substitute 2.69 because that pOH in equation (4).
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Solving for pH,
pH = 11.31
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Grade: High School
Chapter: Acids, base and salts
Keywords: pH, pOH, 11.31, 2.69, 14, 0.002 M, Kb, Kw, Ka, 10^-14, 2*10^-5.
CN^-1 is the conjugate basic of the weak acid HCN ( Ka 3 X 10^-9 )so CN^-1 is a solid base and also will hydrolyze, through the reaction:CN^-1 + H2O --> HCN + OH^-1 Theamount is based on the hydrolysis consistent which is Kw / KaHCN = 1 X 10^-14 / 3 X 10^-9 = 3.333 X 10 ^-6 0.2 M CN^-1 will certainly ionize to a small extent ( A ) to develop A quantities of HCN and A quantities of OH^-1 soo Kh = 3.333 X 10^-6 = / 0.2 -A but A A^2 = 0.2 x 3.333 X 10^-6 A^2= 6.67 X 10^-7 A= 8.17 X 10^-4 pOH = -log ( 8.17 X 10^-4 ) = 3.09then ph ispH = 14 - pOHso pH = 14 - 3.09pH = 10.91