Chemistry, asked by deepuseth4115, 9 months ago

How many grams of NaOH is to be added to one litre of 1 M H.CO, to get a HCO3-/C03-2 buffer of maximum capacity ?​

Answers

Answered by fluffy46
2

Answer:

HA

(

a

q

)

+

OH

(

a

q

)

A

(

a

q

)

+

H

2

O

(

l

)

The number of moles of weak acid and of conjugate base present in the buffer before the addition of the strong base is given by

moles HA

=

moles A

=

0.1 moles

10

3

 

mL

100

mL

moles HA = moles A

=

0.01 moles

Now, if you take  

x

to be the number of moles of sodium hydroxide added to the buffer, you can say that after the reaction is complete, the resulting solution will contain

(

0.01

x

)

 

moles HA

The reaction will consume  

x

moles of the weak acid.

(

0.01

+

x

)

 

moles A

The reaction will produce  

x

moles of the conjugate base.

As you know, the  

pH

of a weak acid-conjugate base buffer can be calculated using the Henderson - Hasselbalch equation.

pH

=

p

K

a

+

log

(

[

A

]

[

HA

]

)

Assuming that the volume of the buffer does not change upon the addition of the strong base, you can say that the volume of the solution after the strong base is added is equal to  

100 mL

.

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