Chemistry Q71 – JEE-MAIN 2025

20 mL of sodium iodide solution gave 4.74 g silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is _________ M. (Nearest Integer value) (Given :

N a = 23

I = 127

A g = 108

N = 14

O = 16 {g mol}^{- 1}

)

Enter Calculated Numerical Value:

Clue 1 of 3: Identify the Reaction

Determine the balanced chemical equation for the reaction between sodium iodide and silver nitrate.

🧠 Full Solution Path

Step 1: Write the Balanced Chemical Equation and Calculate Molar Mass of AgI✦ Active

The reaction between sodium iodide ( $N a I$ ) and silver nitrate ( $A g N O_{3}$ ) produces silver iodide ( $A g I$ ) precipitate and sodium nitrate ( $N a N O_{3}$ ). The balanced chemical equation is:

N a I (a q) + A g N O_{3} (a q) \to A g I (s) + N a N O_{3} (a q)

From the equation, 1 mole of $N a I$ reacts to form 1 mole of $A g I$ . Now, calculate the molar mass of $A g I$ :

M_{A g I} = M_{A g} + M_{I} = 108 + 127 = 235 g/mol

Step 2: Calculate Moles of AgI and NaI○ Expand

Given the mass of $A g I$ formed is $4.74 g$ . We can calculate the moles of $A g I$ :

n_{A g I} = \frac{mass of AgI}{molar mass of AgI} = \frac{4.74 g}{235 g/mol} \approx 0.02017 mol

Since the stoichiometric ratio between $N a I$ and $A g I$ is $1 : 1$ , the moles of $N a I$ in the solution are equal to the moles of $A g I$ formed:

n_{N a I} = n_{A g I} = 0.02017 mol

💡 Teacher's Secret Hint

Ensure you use the correct stoichiometric ratio from the balanced equation.

Step 3: Calculate Molarity of NaI Solution○ Expand

The volume of the sodium iodide solution is $20 mL$ , which is $0.020 L$ . Molarity is defined as moles of solute per liter of solution:

Molarity of NaI = \frac{n_{N a I}}{Volume of solution (L)} = \frac{0.02017 mol}{0.020 L} \approx 1.0085 M

Rounding to the nearest integer value, the molarity of the sodium iodide solution is $1 M$ .

💡 Teacher's Secret Hint

Remember to convert the volume from milliliters to liters before calculating molarity.

✦ STEM Console utilizes AI models to generate step-by-step explanations and math clues. AI can make mistakes.

Chemistry Question 71 – JEE-MAIN 2025

Clue 1 of 3: Identify the Reaction

🧠 Full Solution Path