$BOD$ values (in $ppm$) for clean water $(A)$ and polluted water $(B)$ are expected respectively:

Which of the following processes is $NOT$ used to preserve food?

What concentration of carboxyhaemoglobin complex in the human body reduces the oxygen-carrying capacity of haemoglobin?

Which of the following statements about smog is/are correct?
$(i)$ Smog formed on sunny days contains oxidizing molecules.
$(ii)$ Photochemical smog contains many reactive molecules.
$(iii)$ The main polluting components of smog are oxides of carbon.
$(iv)$ The presence of carbon monoxide in air leads to the formation of ozone in smog.

Which of the following reacts with haemoglobin in the blood to form carboxyhaemoglobin?

Which gas is released into the atmosphere by the exhaust of supersonic jet planes?