Indicators

A solution turns methyl orange into yellow the approximate $\mathrm{pH}$ of solution is

What happens, when methyl orange solution mixed with $\mathrm{HCl}$?

The indicators which turn red in acid solution are:

Which of the following is not an acid-base indicator?

Methyl orange shows _____ colour in acidic medium and yellow colour in basic medium. 

The colour of phenolphthalein indicator in basic solution is:

What is an indicator? Give one example.

What colour does the litmus solution indicator turn when added to a base?

On burning a piece of charcoal, a gas evolves. How is it possible to know whether the gas is acidic or basic in nature.

Which of the following is not a naturally occuring indicator?

Methyl orange changes its colour to yellow when added to a base or an alkali. (True/False)

Select the correct statements regarding solutions given in test tubes $1$ and $2$. 

I. Solution $1$ will turn methyl orange indicator red. 

II. Solution $2$ will turn turmeric indicator red. 

III. Solution $1$ will turn methyl orange indicator yellow. 

IV. Solution $2$ will turn China rose indicator magenta. 

At $25°\mathrm{C}\mathrm{ }\mathrm{p}\mathrm{H}$ range of phenolphthalein is $8\mathrm{ }–\mathrm{ }10$. At $100°\mathrm{C}\mathrm{ }\mathrm{p}\mathrm{H}$ range of phenolphthalein would be-

The rapid change of pH near the stoichiometric point of an acid-base titration is the basis of indicator detection. pH of the solution is related to ratio of the concentrations of the conjugate acid (Hln) and base (ln^-) forms of the indicator by the expression