MyQuestionIcon

1

You visited us 1 times! Enjoying our articles? Unlock Full Access!

Normality

Which of the ...

Question

Which of the following is/are correct for the titration of a mixture of $N a O H$ , $N a_{2} C O_{3}$ and inert substances against $H C l$ ?

A

Phenolphthalein is used to detect the end point when half equivalent of

N a_{2} C O_{3}

and full equivalent of

N a O H

is consumed.

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

B

Phenolphthalein is used to detect the second end point.

No worries! We‘ve got your back. Try BYJU‘S free classes today!

C

Methyl orange is used to detect the final end point.

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

D

Methyl orange is used to detect the first end point.

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct options are
A Phenolphthalein is used to detect the end point when half equivalent of $N a_{2} C O_{3}$ and full equivalent of $N a O H$ is consumed.
C Methyl orange is used to detect the final end point.
Consider a mixture of $N a O H_{(a q)}$ and $N a_{2} C O_{3 (a q)}$ .
Reaction between $H C l_{(a q)}$ and $N a_{2} C O_{3 (a q)}$ takes place in two stages:
$H C l_{(a q)} + N a_{2} C O_{3 (a q)} \to N a H C O_{3 (a q)} + H_{2} O_{(l)} . . . . . . . . . . . . (1)$
$H C l_{(a q)} + N a H C O_{3 (a q)} \to N a C l_{(a q)} + C O_{2 (g)} + H_{2} O_{(l)} . . . . . . . . . . . . (2)$
While that between $H C l_{(a q)}$ and $N a O H_{(a q)}$ completes in only one step:
$H C l_{(a q)} + N a O H_{(a q)} \to N a C l_{(a q)} + H_{2} O_{(l)} . . . . . . . . . . . . (3)$
Solution mixture of reaction $(1)$ at the equivalence point is alkaline, that of reaction $(2)$ is acidic and of reaction $(3)$ is neutral.
Thus, the whole titration should have three breaks in the pH curve, corresponding to the above three stages. Reactions $(1)$ and $(3)$ can be indicated by phenolphthalein and that of reaction $(2)$ can be indicated by methyl orange.

Suggest Corrections

thumbs-up

0

Similar questions

10 g

N a_{2} C O_{3}

N a O H

was titrated against

H C l

by using phenolphthalein followed by adding methyl orange after first equivalence point,

7.7818 g

H C l

was consumed in total. Find the mass of

N a_{2} C O_{3}

in the mixture.

0.4 g

N a O H

N a_{2} C O_{3}

and some inert impurities were first titrated with

\frac{N}{10} H C l

using phenolphthalein as an indicator.

17.5 m L

H C l

was required at the end point. After this methyl orange was added and titrated.

1.5 m L

H C l

was required for the next end point. The weight percentage of

N a_{2} C O_{3}

in the mixture is ______. (Rounded off to the nearest integer)

Q. A solution contains a mixture of

N a_{2} C O_{3}

N a O H .

Using phenolphthalein as indicator

35 m L

of mixture required

20 m L

0.80 N H C l

for the end point. With methyl orange,

35 m L

of solution required

37.5 m L

H C l

for the end point. What is the weight of

N a_{2} C O_{3}

N a O H

respectively in the mixture?

0.6234

g sample that might contain

N a O H, N a_{2} C O_{3}, N a H C O_{3}

or a mixture of

N a O H + N a_{2} C O_{3}

N a_{2} C O_{3} + N a H C O_{3}

is titrated with

0.1062 M H C l

by two-indicator method. It is found that

40.38

mL of the acid is required to reach the phenolphthalein end-point. Methyl orange is then added to the solution and the titration continued using an additional

12.83

mL of the acid. Thus, the sample contained :

Q. A solution contains a mixture of

N a_{2} C O_{3}

N a O H .

Using phenolphthalein as indicator

35 m L

of mixture required

20 m L

0.80 N H C l

for the end point. With methyl orange,

35 m L

of solution required

37.5 m L

H C l

for the end point. What is the weight of

N a_{2} C O_{3}

N a O H

respectively in the mixture?

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Reactions in Solutions

CHEMISTRY

Watch in App

explore_more_icon

Explore more

Standard XII Chemistry

Join BYJU'S Learning Program

CrossIcon