Methyl orange is
a. pink in acidic medium, yellow in basic medium
b. yellow in acidic medium, pink in basic medium
c. colorless in acidic medium, pink in basic medium
d. pink in acidic medium, colorless in basic medium.

 a. Pink in acidic medium, yellow in basic medium

Explanation:  Methyl orange is a type of  pH indicator which is used in the titration of acids and bases in order to achieve an end point in the process so as to determine the amount of acid that has been neutralized by the base itself.

The color it presents in acidic medium is red rather pink and it actually shows yellow color in basic medium.

It turns red below 3.3 pH and above 4.4, it shows yellow color. Thus sometimes, it is not recommended for the neutralization reaction.

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"