Answer:
0.866
Explanation:
To solve this problem, first, we need to calculate the molarity of Ca(OH)2. This is shown below:
Molar Mass of Ca(OH)2 = 40 + 2(16+1) = 40 + 2(17) = 40 + 34 = 74g/mol
Mass of Ca(OH)2 = 2.5g
Number of mole of Ca(OH)2 =?
Number of mole = Mass /Molar Mass
Number of mole of Ca(OH)2 = 2.5/74 = 0.034 mole
Now we can obtain the molarity as shown below:
Volume = 500mL = 500/1000 = 0.5L
Mole = 0.034 mole
Molarity = mole/Volume
Molarity = 0.034/0.5
Molarity = 0.068M
Next, let us generate a balanced dissociation equation for Ca(OH)2. This is illustrated below:
Ca(OH)2 —> Ca^2+ + 2OH^-
From the equation above,
1 mole of Ca(OH)2 produced 2 moles of OH^-.
Therefore, 0.068M of Ca(OH)2 will produce = 0.068M x 2 = 0.136M of OH^-.
Now we can calculate the pOH as follow:
[OH^-] = 0.136M
pOH = — Log [OH^-]
pOH = — Log 0.136
pOH = 0.866
