Question

Polychlorinated biphenyls (PCBs), which were formerly used in the manufacture of electrical transformers, are environmental and health hazards. They break down very slowly in the environment. The decomposition of PCBs can be represented by the equation:

Answer 1

The decomposition of PCBs is given as:

`2C_(12)H_(4)Cl_(16)+23O_2+2H_2O \rightarrow 24CO_2 + 12HCl`

Step-by-step explanation:

Polychlorinated biphenyls are synthetic chemicals including two benzene rings with chlorine atom attached to the ring. Yellow in color with no taste and odor.

The decomposition of PCBs is given as:

`2C_(12)H_(4)Cl_(16)+23O_2+2H_2O \rightarrow 24CO_2 + 12HCl`

According to reaction, 2 moles of PCBS reacts with 23 moles of oxygen gas and 2 moles of water to gives 24 moles of carbon dioxide and 12 moles of hydrochloric acid.

Answer 2

C12H4Cl6 + 23 O2 + 2 H2O → 24 CO2 + 12 HCl

(a)
(13.5 mol O2) x (2 mol H2O / 23 mol O2) = 1.17 mol H2O

(b)
(17.6 mol H2O) x (12 mol HCl / 2 mol H2O) x (36.4611 g HCl/mol) = 3850 g HCl

(c)
(90.4 g HCl) / (36.4611 g HCl/mol) x (24 mol CO2 / 12 mol HCl) = 4.96 mol CO2

(d)
(106.01 g CO2) / (44.00964 g CO2/mol) x (2 mol C12H4Cl6 / 24 mol CO2) x (360.8782 g C12H4Cl6/mol) =
72.4 g C12H4Cl6

(e)
(4.2 kg C12H4Cl6) / (360.8782 g C12H4Cl6/mol) x (12 mol HCl / 2 mol C12H4Cl6) x (36.4611 g HCl/mol) =
2.5 kg HCl