${\mathrm{Na}}_2{\mathrm{B}}_4{\mathrm{O}}_7$ gives ${\mathrm{H}}_3{\mathrm{BO}}_3$ and $\mathrm{NaOH}$ (strong base) in water.

So, it is a salt of strong base and weak acid. So, its solution will be strongly basic in water. It will have very high pH.

Lithium borohydride and sodium borohydride reacts with water to produce hydrogen.

And diborane act as lewis acid.