How much will the temperature of water weighing 20 kg increase if you transfer to it the entire amount

How much will the temperature of water weighing 20 kg increase if you transfer to it the entire amount of heat from the combustion of 2 kg of firewood.

Initial data: m1 (water mass) = 20 kg; m2 (mass of burnt wood) = 2 kg.

Constants: C (specific heat capacity of water) = 4200 J / (kg * K); q (specific heat of combustion of dry wood) = 1 * 10 ^ 7 J / kg.

If we assume that all the heat from combustion goes to changing the temperature of the water, then the ratio is true:

Q1 = Q2: C * m1 * Δt = q * m2.

Δt = q * m2 / (C * m1).

Δt = q * m2 / (C * m1) = 1 * 10 ^ 7 * 2 / (4200 * 20) = 238 ºС (impossible, after reaching the temperature of 100 ºС the process of water evaporation will occur).