List of top Environmental Chemistry Questions

Correctly label the speciation diagram below:


 

A researcher added a certain amount of HgCl2 to water at pH 10. He calculated the expected concentration of mercury in the water. He asked his student to measure the concentration. His student used an instrument that can measure only the free metal, Hg2+. The student observed that the concentration measured by him was significantly less than the concentration calculated by the researcher. How can he explain the paradox to the researcher?
Choose the correct option(s) from the following regarding cumulative toxicity:
Choose the correct option(s) from the following regarding the urban environment:
Methane hydrates have a special crystal structure of water, where methane gas molecules are trapped. Choose the correct option(s) from the following:

Consider the following statements: 
(i) Environmental pollutant concentration is generally modeled using lognormal distribution. 
(ii) Environmental pollutant concentration is generally modeled using Poisson distribution. 
(iii) The weekly rate of exceedance of environmental pollutant concentration with regards to a given standard is generally modeled using lognormal distribution. 
(iv) The weekly rate of exceedance of environmental pollutant concentration with regards to a given standard is generally modeled using Poisson distribution. 
Choose the correct option(s) from the following:

Consider the following statements:

P: According to the National Ambient Air Quality Standards (Central Pollution Control Board, Govt. of India, notification 2009), annual time-weighted average \( \text{PM}_{10} \) standard is more than \( \text{PM}_{2.5} \) standard.

Q: According to the National Air Quality Index released by Govt. of India in 2015, sub-index value of \( \text{PM}_{10} \) can be less than that of \( \text{PM}_{2.5} \).

Choose the correct option from the following:

Match the following and choose the correct option from the following:

Note: The symbol indicates a stirrer for mixing (not to scale).

Choose the redox reaction from the following:
Hardness in water is NOT caused by ______
The maximum coordination number of \( \text{Sn}^{4+} \) is \(\_\_\_\_\)
Which one of the following conversions belongs to nonsymbiotic nitrogen fixation?
The environmental temperature increases by 6°C/km with height at a particular location. The stability condition of the atmosphere at the location is ______,
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 Streeter-Phelp's oxygen sag equation for a river is based on a few assumptions. The correct assumption(s) is/are
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 concentration of Ozone corresponding to a mixing ratio of 120 ppbv at pressure of 1 atmosphere and temperature of 25°C is ________ \(μg/m^3\) (rounded off to 1 decimal place).
Atomic weight of oxygen = 16; R= 8.314 J/K-g.mole.
In a region, total annual consumption of gasoline is 30.6 million tons. The land required for growing sugarcane to produce enough bioethanol to replace the gasoline completely is ___________ \(km^2\) (an integer value). 
Ethanol energy equivalent is 67% of gasoline, gasoline density is 850 \(kg/m^3\), yield of bioethanol produced from sugarcane per hectare of land is 3750 L, and 1 \(km^2\) = 100 hectares
Initially a bottle contained 400 g of ethanol. Half of ethanol was used by a student for preparing the stock solution in an environmental chemistry laboratory just before summer vacation of 90 days. After completing the procedure, the student left the bottle uncorked. If the unsealed bottle losses ethanol at a rate of 0.5 g/day, the ethanol that will be left in the bottle at the end of the summer vacation is __________ g (an integer value).