Highly selective Backlog Qs for JEE MainChemistryRedox Reactions
An alkali is titrated against acid with methyl orange as an indicator, which of the following is a correct combination?
Options
- AB a s e A c i d E n d p o i n t S t r o n g S t r o n g P i n k t o c o l o u r l e s s
- BB a s e A c i d E n d p o i n t W e a k S r t o n g C o l o u r l e s s t o p i n k
- CB a s e A c i d E n d p o i n t S t r o n g s t r o n g P i n k i s h r e d t o y e l l o w
- DB a s e A c i d E n d p o i n t W e a k S t r o n g Y e l l o w t o p i n k i s h r e d
Correct answer
D. B a s e A c i d E n d p o i n t W e a k S t r o n g Y e l l o w t o p i n k i s h r e d
Step-by-step solution
The pH range between 3 . 1 (red) and 4 . 4 (yellow) is the colour-change interval of methyl orange. Weak base has pH > 7 . So, when methyl orange indicator is added the solution turns yellow & if the solution is titrated against strong acid it turns pinkish red at the end point i.e., pH < 3 . 1 .