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Question: \( 7.3grams \) of \( Hcl \) is dissolved in \( 20litre \) solution. \( 50ml \) of this solution is t...

7.3grams7.3grams of HclHcl is dissolved in 20litre20litre solution. 50ml50ml of this solution is taken in 250ml250ml flask and water is added up to the mark. 40ml40ml if this diluted HclHcl solution exactly neutralizes 20ml20ml of Ba(OH)2Ba{(OH)_2} solution. pH of given hydroxide solution is:
A)2.699 \\\ B)12.301 \\\ C)7.902 \\\ D)11.601 \\\

Explanation

Solution

Hint : pH is a proportion of how acidic/basic water is. The reach goes from 0to140to14 . The pH under 7 considered as acids and pH of more prominent than 77 demonstrates basic behavior, while with 77 being neutral. pH is actually a proportion of the general measure of free hydrogen and hydroxyl particles in the water.

Complete Step By Step Answer:
Firstly, we will calculate the number of moles of HclHcl
We know that the formula of the number of moles = MassMolarmass\dfrac{{Mass}}{{Molarmass}} .
By this, we can calculate the molality of the solution
= molesofsolutevolumeinlitre\dfrac{{moles of solute}}{{volume in litre}} = 0.220\dfrac{{0.2}}{{20}} .
MHcl=10−2{M_{Hcl}} = {10^{ - 2}}
Now, we know 50ml50ml solution is diluted in 250ml250ml .
The new concentration will be
= M1V1=M2V2{M_1}{V_1} = {M_2}{V_2} .
= 0.01M×50ml=M2×250ml0.01M \times 50ml = {M_2} \times 250ml
So the M2{M_2} is 2×10−3M2 \times {10^{ - 3}}{M_{}}
When 40ml40ml of this solution is diluted 20ml20ml of Ba(OH)2Ba{(OH)_2} .The concentration of Ba(OH)2Ba{(OH)_2} is
= 40×2×10−3=20×M3×240 \times 2 \times {10^{ - 3}} = 20 \times {M_3} \times 2
= M3=2×10−3M{M_3} = 2 \times {10^{ - 3}}M
The concentration of OH−O{H^ - } will be
= [O{H^ - }] = 2 \times (2 \times {10^{ - 3}}) \\\ = [O{H^ - }] = 4 \times {10^{ - 3}}M \\\
Now, we will calculate the pH
pOH = - Log[OH] = 2.397 \\\ pH = 14 - 2.397 \\\ pH = 11.6 \\\
So, the pH of Ba(OH)2Ba{(OH)_2} IS 11.6.
Correct answer is D)D) .

Note :
By the use of filter paper we can find the pH of aqueous arrangement by treating it with the pH indicator. Litmus paper will be paper that has been treated with a particular indicator—a combination of 10 to 15 normal colors obtained from lichens that becomes red because of acidic conditions (pH 7). At the point when the pH is impartial (pH = 7), at that point the color is purple.