Question

Why is t-butyl alcohol soluble in water?

Answer 1

What is the similarity between `(H_3C)_3COH` and `HOH`? The hydroxyl group?

Explanation:

Clearly, `"tert-butanol"` has some similarity with the water molecule. And that similarity is the hydroxyl group. You should look up the aqueous solubility. It would not be immiscible; by the same reasoning it would not be infinitely miscible, as is methanol and ethanol.

A good comparison would be the solubility of `"n-butanol"` and `"sec-butanol"` in aqueous solution. As a prediction, which certainly might be mistaken, `"tert-butanol"`, might be more soluble than `"n-butanol"`, but as chemists, as physical scientists, we should always seek out the data to inform our arguments, and never the other way round.