In the manufacture of nitric acid, ammonia and preheated air are mixed to form a gas containing 10 mole% NH3 at 600oC. (The ammonia is not preheated, since if it were, it will decompose to N2 and H2). The mixture is then catalytically oxidized to form NO2, which is absorbed in water to form HNO3. If ammonia enters the gas blending (mixing) unit at 25oC at a rate of 520 kg/h, and heat is lost from the mixer to its surroundings at a rate of 7 kW, determine the temperature to which the air must be preheated. (Use the first two terms of the Cp equation for air).

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l