The Rf value of compound A is 0.35 when TLC plate is developed in hexane and 0.45 when the plate is developed in diethyl ether. Compound B has an Rf value of 0.45 in hexane and 0.60 in diethyl ether. Hexane would be better for separating a mixture of compounds A and B by TLC. If yes then why?

No.

Explanation:

Under TLC chromatography, the compounds are separated based on the different affinity between stationary phase and mobile phase. The higher difference between Rf's of the compounds will produce the better separation.

In Hexane compound A has a Rf of 0.35 and compound B of 0.45.

The difference is 0.45 - 0.35 = 0.10

In dietyl ether, Rf of compound A is 0.45 and for compound B is 0.60.

The difference is 0.60 - 0.45 = 0.15.

As the difference in Rf is higher for dietyl ether:

Hexane would be better for separating a mixture of compounds A and B by TLC. NO. The better separation would be using dietyhl ether.

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.