Question

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

Answer 1

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.

Answer 2

Answer ⇒ Universal indicator.

Explanation ⇒  We know that Litmus paper is generally of two types, Blue Litmus Paper and Red Litmus Paper.

Blue Litmus Paper turns Red when Acids.  are added to it and Red Litmus Paper turns Blue when Bases are added to it.

Methyl orange turns red when acids are added to it and turns yellow when bases are added to it.

Similarly,  Phenopthalein turns pink when bases are added and remains colorless when acids are added to it.  

But in case of the Universal Indicator, It indicates the acidic nature by the pH value Calculations. So it is little different from them.

Hence, Universal Indicator is the odd one out.

Hope it helps.