For an acid indicator with $K_{in} = 1.0 \times 10^{-5}$, the color change occurs when the concentration of the indicator is $1 \times 10^{-3} \ M$. Find the $pH$ at which the color change occurs.

Given below are two statements.
Statement $I:$ In the titration between a strong acid and a weak base,methyl orange is a suitable indicator.
Statement $II:$ For the titration of acetic acid with $NaOH$,phenolphthalein is not a suitable indicator.
In the light of the above statements,choose the most appropriate answer from the options given below:

Methyl orange gives $.......$ color in an acidic medium.

The best indicator for the detection of the end point in the titration of a weak acid and a strong base is:

$A$ $0.1 \ N$ solution of $Na_2CO_3$ is titrated with $0.1 \ N$ $HCl$ solution. The best indicator to be used is

$50 \ mL$ of $0.1 \ M$ of a weak acid $HA$ is titrated with $0.1 \ M$ of $NaOH$. The ionization constant of $HA$ $(K_a)$ is $1.8 \times 10^{-5}$. Using the given information and from the options shown below,the best indicator for the titration of $HA$ with $NaOH$ is $....$