Both alkali metals are exceptionally reactive, and would reduce water to give dihydrogen.
#NaK# alloy, as used in the laboratory is an amalgam of sodium and potassium metals. It is commonly used as a drying agent for ethers and hexanes, in that its melting point is much lower than either of the metals used to prepare it, and is low enough that it remains a molten globule at low temperature. It would react spectacularly with water, but the products would be #KOH# and #NaOH#.
The reaction between water and #NaK# alloy is not one that anyone should attempt. Potassium is reactive; the alloy is even more so; do not let it come near water. I am willing to tell you how to dispose of #NaK# alloys in a personal message.