List of top Environmental Chemistry Questions on Solutions asked in GATE ES

A saturated \(CaCO_3 \)stock solution is existing at 25°C. In one experiment (i) 25 g \(Na_2CO_3 \)is added to the stock solution. In another experiment (ii) 25 g \(Na_2SO_4\) is added to the stock solution. Select the correct statement from the following.
The pH of a solution containing 0.1M of acetic acid and 0.05 M of sodium acetate is ________ (rounded off to 2 decimal places).
The $pK_a$ value of ionization of acetic acid is 4.76.
The ionic strength of a solution containing 0.01M of $CaCl_2$ and 0.001M of $Na_2SO_4$ is _____ M (rounded off to 3 decimal places)
The ratio of the moles of CO$_2$ evolved to the moles of O$_2$ consumed in respiration, also called the respiratory quotient (RQ), is calculated for a carbohydrate (C$_6$H$_{12}$O$_6$) as substrate and found to be 1. Under similar conditions, for a fatty acid (C$_{51}$H$_{98}$O$_6$) as substrate, the respiratory quotient is ________________ (rounded off to two decimal places).
River water containing two types of spherical suspended particles (clay particles, metal particles) is retained in a sedimentation tank. The clay particles having diameter of 75 $\mu$m and specific gravity of 2.65 is settling in the tank with a constant velocity. The velocity of clay particles is 2 times that of metal particles having specific gravity of 8. Assume discrete settling and laminar flow conditions within the sedimentation tank. The estimated diameter of the metal particles is ________________________ (in $\mu$m, rounded off to integer).
A solution has 0.001 mole/L zinc ions with pH = 6. The solubility product of zinc hydroxide is \[ K_{sp} = 8 \times 10^{-18}\ (\text{mol/L})^{3}. \] Ignoring activity corrections, find the ratio (rounded to two decimals) of the reaction quotient to the solubility product.