How Calculate N Moles of Onp Formed

Calculating the number of moles of ortho-nitrophenol (ONP) formed in a chemical reaction is essential for understanding reaction stoichiometry and yield. This guide explains the process step-by-step and provides a calculator for quick results.

What is ONP?

Ortho-nitrophenol (ONP) is a chemical compound with the formula C₆H₅NO₃. It's a derivative of phenol where a hydroxyl group is replaced by a nitro group, and the nitro group is ortho to the hydroxyl group. ONP is commonly used in organic synthesis and as a reagent in chemical reactions.

ONP is highly soluble in water and organic solvents, making it useful in various chemical processes. It's often prepared through nitration of phenol followed by purification steps.

How to Calculate Moles of ONP Formed

The number of moles of ONP formed can be calculated using stoichiometry principles. The key steps are:

Determine the balanced chemical equation for the reaction
Identify the limiting reactant
Use the mole ratio from the balanced equation
Calculate the moles of ONP formed

n = (moles of limiting reactant) × (mole ratio of ONP)

Where:

n = moles of ONP formed
moles of limiting reactant = mass of limiting reactant / molar mass of limiting reactant
mole ratio = coefficient of ONP in balanced equation / coefficient of limiting reactant in balanced equation

For example, in the reaction of phenol with nitric acid to form ONP:

C₆H₅OH + HNO₃ → C₆H₄(NO₂)OH + H₂O

The mole ratio of ONP to phenol is 1:1.

Example Calculation

Let's calculate the moles of ONP formed when 50 grams of phenol reacts with excess nitric acid.

Calculate moles of phenol: 50 g / 94.11 g/mol = 0.531 moles
Using the 1:1 mole ratio, moles of ONP formed = 0.531 moles

Result

0.531 moles of ONP are formed.

This example assumes complete reaction and ideal conditions. In practice, factors like reaction yield and purity of reactants may affect the actual amount of ONP formed.

Factors Affecting the Result

Several factors can influence the calculation of moles of ONP formed:

Reaction yield: Not all reactions proceed to completion
Purity of reactants: Impurities can affect stoichiometry
Temperature: Can affect reaction rate and equilibrium
Catalyst presence: May alter reaction pathway
Side reactions: May consume reactants or produce byproducts

Comparison of Theoretical and Actual ONP Yields
Factor	Theoretical Yield	Actual Yield (Typical)
Ideal conditions	100%	85-95%
Impure reactants	100%	70-80%
Side reactions	100%	60-75%

FAQ

What is the molar mass of ONP?: The molar mass of ONP (C₆H₅NO₃) is approximately 139.11 g/mol.
How do I determine the limiting reactant?: Compare the mole ratios of reactants to the stoichiometric coefficients in the balanced equation. The reactant that produces fewer moles of product is the limiting reactant.
What if the reaction doesn't go to completion?: You can adjust the calculation by multiplying the theoretical moles by the reaction yield percentage. For example, if the yield is 80%, multiply the theoretical moles by 0.8.
Can ONP be isolated from the reaction mixture?: Yes, ONP can be isolated through techniques like recrystallization or extraction with appropriate solvents, followed by drying.