An iodized salt contains 0.5% of NaI. A person consumes 3 gm of salt everyday. The number of iodide ions going into his body everyday is (I = 127 )

Options

A. `10^(-4)`
B. `6.02xx10^(-4)`
C. `6.02xx 10^(19)`
D. `6.02xx 10^(23)`

Answer

To solve the problem step by step, we will follow the given information and apply the necessary calculations.

### Step 1: Calculate the weight of NaI in 3 grams of salt
The iodized salt contains 0.5% of NaI. This means that in 100 grams of salt, there are 0.5 grams of NaI.

To find the weight of NaI in 3 grams of salt:
\[ \text{Weight of NaI} = \frac{0.5}{100} \times 3 = 0.015 \text{ grams} = \frac{15}{1000} \text{ grams} \]

### Step 2: Calculate the molar mass of NaI
The molar mass of NaI can be calculated by adding the atomic masses of sodium (Na) and iodine (I).
- Atomic mass of Na = 23 g/mol
- Atomic mass of I = 127 g/mol

Thus, the molar mass of NaI is:
\[ \text{Molar mass of NaI} = 23 + 127 = 150 \text{ g/mol} \]

### Step 3: Calculate the number of moles of NaI
Using the weight of NaI calculated in Step 1 and the molar mass from Step 2, we can find the number of moles of NaI:
\[ \text{Number of moles of NaI} = \frac{\text{Weight of NaI}}{\text{Molar mass of NaI}} = \frac{15 \times 10^{-3} \text{ g}}{150 \text{ g/mol}} = 10^{-4} \text{ moles} \]

### Step 4: Determine the number of iodide ions (I⁻)
Since NaI dissociates completely in solution, the number of moles of iodide ions (I⁻) will be equal to the number of moles of NaI:
\[ \text{Moles of I⁻} = 10^{-4} \text{ moles} \]

### Step 5: Calculate the number of iodide ions
To find the total number of iodide ions, we multiply the number of moles of iodide ions by Avogadro's number (approximately \(6.022 \times 10^{23}\) mol⁻¹):
\[ \text{Number of iodide ions} = \text{Moles of I⁻} \times \text{Avogadro's number} = 10^{-4} \times 6.022 \times 10^{23} \approx 6.022 \times 10^{19} \text{ ions} \]

### Final Answer
The number of iodide ions going into the person's body every day is approximately \(6.022 \times 10^{19}\).

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