The first step in the industrial manufacture of nitric acid is the catalytic oxidation of ammonia.

[tex]\[ NH_3 + O_2 \rightarrow NO + H_2O \ \text{(unbalanced)} \][/tex]

The reaction is run using 824 g of [tex]\( NH_3 \)[/tex], and excess oxygen. How many grams of [tex]\( NO(g) \)[/tex] are formed?

A. 727 g
B. 192 g
C. 1454 g
D. 893 g



Answer :

To determine how many grams of NO (nitric oxide) are formed from the catalytic oxidation of ammonia (NH₃) with excess oxygen (O₂), let's walk through the problem step-by-step:

### Step 1: Write and Balance the Chemical Equation

The unbalanced reaction is:
[tex]\[ \text{NH}_3 + \text{O}_2 \rightarrow \text{NO} + \text{H}_2 \text{O} \][/tex]

Balanced chemical equation:
[tex]\[ 4 \text{NH}_3 + 5 \text{O}_2 \rightarrow 4 \text{NO} + 6 \text{H}_2 \text{O} \][/tex]

### Step 2: Calculate the Molar Masses of NH₃ and NO

The molar masses of the involved compounds are:
- NH₃: [tex]\( 1 \times 14.01 + 3 \times 1.01 = 17.03 \, \text{g/mol} \)[/tex]
- NO: [tex]\( 1 \times 14.01 + 1 \times 16.00 = 30.01 \, \text{g/mol} \)[/tex]

### Step 3: Convert Mass of NH₃ to Moles

To find the number of moles of NH₃:
[tex]\[ \text{mass of NH}_3 = 824 \, \text{g} \][/tex]
[tex]\[ \text{molar mass of NH}_3 = 17.03 \, \text{g/mol} \][/tex]
[tex]\[ \text{moles of NH}_3 = \frac{824 \, \text{g}}{17.03 \, \text{g/mol}} \approx 48.39 \, \text{moles} \][/tex]

### Step 4: Use the Mole Ratio to Determine Moles of NO

From the balanced equation, the mole ratio of NH₃ to NO is 1:1. Therefore, the number of moles of NO formed is the same as the moles of NH₃ used:
[tex]\[ \text{moles of NO} = 48.39 \, \text{moles} \][/tex]

### Step 5: Convert Moles of NO to Mass

To find the mass of NO formed:
[tex]\[ \text{molar mass of NO} = 30.01 \, \text{g/mol} \][/tex]
[tex]\[ \text{mass of NO} = \text{moles of NO} \times \text{molar mass of NO} \][/tex]
[tex]\[ \text{mass of NO} = 48.39 \, \text{moles} \times 30.01 \, \text{g/mol} \approx 1452.04 \, \text{g} \][/tex]

### Conclusion:
The mass of NO formed is approximately 1452 grams.

Thus, the correct choice among the given options is:
[tex]\[ 1454 \, \text{g} \][/tex] (Round to nearest value provided in the options)

Therefore, 1454 grams of NO are formed in the reaction.