Environmental chemistry

Ammonium salt in rain drop resulting wet deposition

$N{H}_4^{+}?Salt+H_{2}O?N{H}_{4}OH$

Oxides of N & S settle down on ground as dry deposition (SO₂).

Hydrogen peroxide reduces iodine to iodide ion is basic medium as;

$H_2{O}_2+2O{H}^{-}+l_2\to O_2+2l^{-}+2H_{2}O$

B. O. D. value < 5 ppm for clean water and B.O.D value of polluted water 17 ppm.

In stratosphere CFC get broker down by powerful UV/radiation releasing Cl^·

$CF{}_{2}C{l}_2\left(g\right)\stackrel{UV}{\to }C{l}^{•}\left(g\right)+C^{•}{F}_{2}Cl\left(g\right)$

Assertion : Clean water has BOD less than 5ppm. Highly polluted water has BOD greater than or equal to 17 ppm.

Reason : BOD is measure of oxygen required to oxidize only bio-degradable organic matter.

Thus Assertion (A) is correct & Reason (R) is wrong.

Funnel of option A is useful for the separation of liquid – liquid mixture of immiscible form.

Following are the component of photochemical smog,

$C{H}_4+O_3\stackrel{}{\to }HCHO+H_{2}O+C{H}_2\text{?}=\text{?}CH-CHO+C{H}_{3}COON{O}_3$

Photochemical smog generally does not content SO₂ gas.

(A) Sulphate (>500 ppm) ® causes laxative effect that leads to dehydration.

(B) Nitrate (> 50 ppm) ® causes methemoglobinemia, skin appears blue.

(C) Lead (>50 ppb) ® It damage kidney and RBC.

(D) Fluoride (>2ppm) ® It causes brown mottling of teeth.

(a) Polluted water has low value of dissolved oxygen, but high value of B.O.D., because chemical and organic matter uses dissolved oxygen to decompose.

(b) Eutrophication is result of excessive growth of weed in water bodies, which consumes dissolved oxygen, thus decreases oxygen.