Question

Find odd man out 1.litmus 2.methyl orange 3.phenolphthalein 4.universal indicator

Answer 1

Odd man Out : Option is 1. Litmus 

Reason :
Litmus is the natural indicator which is extracted from the lichen plant and helps us to identify whether the given substance is acidic or basic.

methyl orange ,phenolphthalein , universal indicator are the synthetic indicators which are prepared from chemicals 

Answer 2

Hey there!

Given Options ->
1.litmus
2.methyl orange
3.phenolphthalein
4.universal indicator

We see that all share a common propery that they are indicators. But the Odd one is Universal indicator.

Litmus paper turns blue or red to show that they are basic or acidic . Methyl orange also turns yellow or red to indicate acidic nature and basic nature . Phenopthalein turns pink, or colourless to indicate acidic and basic natures.

So, It is evident that Litmus, Methyl orange, Phenopthalein share a common property that they can change colors to indicate the nature of the substance either basic or acidic or neutral.

But Universal indicator can turn to different colors at different ranges of PH which makes it a go to indicator for all things.

Hence, Odd one out is Universal indicator.