Class 12th

O₃ generally exist in stratosphere and they acts as protector, because it protect us from harmful UV radiations but sometimes O₃ formed in troposphere and it acts as a pollutants.

O₃ in stratosphere : - Protector

O₃ in Troposphere : - Pollutant (photochemical smog)

Kernite $\left(N{a}_2{B}_4{O}_7.4H_{2}O\right)\to$ it is ore of boron

Cassiterite (SnO₂) → it is ore of tin

Calamine (ZnCO₃) → it is ore of zinc

Cryolite (Na₃AlF₆) → it is ore fluorine

Option (A) is false statement because estimation of nitrogen in an organic compound is done by Kjeldahl's method.

PbO₂ is used is lead storage battery and is amphoteric as strong oxidizing agent since Pb (II) is more stable than Pb (IV).

$N{H}_3+\underset{A}{H_{2}O}+C{O}_2\to {\left(N{H}_4\right)}_{2}C{O}_3$

${\left(N{H}_4\right)}_{2}C{O}_3+H_{2}O+\underset{B}{C{O}_2}\to N{H}_{4}HC{O}_3$

$N{H}_{4}HC{O}_3+NaCl\to N{H}_{4}Cl+\underset{C}{NaHC{O}_3}$

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