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.
