List of top Water Resources and Environmental Hydraulics Questions on Water: Structure, properties and distribution asked in GATE ES

The solubility of gas A is 16 mg/L in water and its vapor pressure is 0.042 atm at 25\(^\circ\)C. In a closed system, the gas phase concentration of A is \(10^{-3}\) mol/L. Assuming ideal gas constant \(R = 0.0821 \, \text{L atm mol}^{-1}\text{K}^{-1}\), the concentration of gas A in water at 25\(^\circ\)C is ............ (in mg/L, rounded off to two decimal places).
A BOD\(_5\) test is conducted. 25 mL wastewater with ultimate BOD of 75 mg/L is diluted to 300 mL. Initial DO = 6.5 mg/L. DO at 7th day = 1.25 mg/L. Find BOD\(_5\) of wastewater sample (mg/L, rounded off to two decimals).
A venturimeter with a differential manometer is installed to measure flow in a water pipeline. Taking water specific weight = 9810 N/m$^3$, compute the pressure difference (in Pa, rounded off to one decimal place) between points Q and P.
The correct order of hydraulic conductivity for the geologic formations is