> How many of the following will evolve $\ce{H2}$ gas when dissolved in water under room conditions?
>
> $\ce{B2H6},$ $\ce{SiH4},$ $\ce{CH4},$ $\ce{Al},$ $\ce{B},$ $\ce{Na},$ $\ce{PCl3},$ $\ce{P(white)},$ $\ce{Fe}.$

Initially, it seemed easy to me and I got 7 (all except $\ce{PCl3},$ $\ce{CH4}).$ Correct me if I am wrong here.

However, the answer given was 3, which given were most likely $\ce{B2H6},$ $\ce{SiH4}$ and $\ce{Na}.$

What did I do wrong here? Does the temperature condition hold that much difference here? How do you predict products like these?