Thermal conductivity of water ______ with rise in temperature.
Right Answer is:
May increase or decrease depending upon temperature
The thermal conductivity of water may increase or decrease depending upon temperature with rise in temperature.
Unlike other liquids, the thermal conductivity of water (k) increases as the temperature increases, but this happens only up to 130°C. Beyond 130°C, k values decrease with temperature.
For water below 130°C., as the temperature increases, water molecules exist as a cluster due to hydrogen bonds, so instead of each molecule being further apart, collision velocity increases. Thus, higher thermal conductivity.
However, beyond 130C in which most hydrogen bonds are already broken, water molecules are now behaving like normal liquids as the temperature goes up. This means that beyond 130°Ccollision distance of water molecules governs the thermal conductivity. Hence thermal conductivity decrease.