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- Some Basic Concepts of Chemistry
NEET · Chemistry · Some Basic Concepts of Chemistry
The sample containing same no. of ' Na ' atom as there are ' Na '...
The sample containing same no. of ' Na ' atom as there are ' Na ' atoms in 5.3 g of (\mathrm{Na}_2 \mathrm{CO}_3) is -
(A) 4 g of NaOH
(B) 5.85 g of NaCl
(C) 0.25 mol of (\mathrm{Na}_2 \mathrm{SO}_4)
(D) 5.6 g of (\mathrm{Na}_3 \mathrm{PO}_4)
Options
- AA & C both are correct.
- BB & D both are correct.
- CA & B are correct.
- DC & D both are correct.
Correct answer
C. A & B are correct.
Step-by-step solution
Step 1: Calculate moles of Na in 5.3 g of (\mathrm{Na}_2 \mathrm{CO}_3)
Molar mass of (\mathrm{Na}_2 \mathrm{CO}_3) :
- (\mathrm{Na}=23, \mathrm{ g} / \mathrm{mol}(2 \mathrm{Na}=46 \mathrm{ g}))
- (\mathrm{C}=12, \mathrm{ g} / \mathrm{mol})
- (\mathrm{O}=16, \mathrm{ g} / \mathrm{mol}(3 \mathrm{O}=48 \mathrm{ g}))
Total:
(46+12+48=106 \mathrm{ g} / \mathrm{mol})
Moles of (\mathrm{Na}_2 \mathrm{CO}_3) in 5.3 g :
Moles (=\frac{5.3 \mathrm{ g}}{106 \mathrm{ g} / \mathrm{mol}} \approx 0.050 \mathrm{ mol})
Number of Na atoms in (\mathrm{Na}_2 \mathrm{CO}_3) :
(0.050 \mathrm{ mol} \times 2=0.100 \mathrm{ mol}) of Na
Step 2: Determine equivalent samples
(A) 4 g of INaOII:
- Molar mass of
(\mathrm{NaOHI}=23+16+1=40, \mathrm{ g} / \mathrm{mol})
Moles of (\mathrm{Na}=\frac{4 \mathrm{ g}}{40 \mathrm{ g} / \mathrm{mol}}=0.1 \mathrm{ mol})
(B) 5.85 g of NaCl :
- Molar mass of (\mathrm{NaCl}=23+35.5=58.5, \mathrm{ g} / \mathrm{mol})
Moles of (\mathrm{Na}=\frac{5.85 \mathrm{ g}}{58.5 \mathrm{ g} / \mathrm{mol}} \approx 0.1 \mathrm{ mol})
(C) 0.25 mol of (\mathrm{Na}_2 \mathrm{SO}_4) :
- (\mathrm{Na}_2 \mathrm{SO}_4) has 2 Na per formula unit.
Moles of (\mathrm{Na}=0.25 \times 2=0.5 \mathrm{ mol}) (inc
(D) 5.6 g of (\mathrm{Na}_3 \mathrm{PO}_4) :
- Molar mass of
(\mathrm{Na}_3 \mathrm{PO}_4 \mathrm{ g}^f \times 23+31+4 \times 16=)
- Molar mass of
(\mathrm{NaCl}=23+35.5=58.5, \mathrm{ g} / \mathrm{mol})
Moles of (\mathrm{Na}=\frac{5.85 \mathrm{ g}}{58.5 \mathrm{ g} / \mathrm{mol}} \approx 0.1 \mathrm{ mol})
(C) 0.25 mol of (\mathrm{Na}_2 \mathrm{SO}_4) :
- (\mathrm{Na}_2 \mathrm{SO}_4) has 2 Na per formula unit.
Moles of (\mathrm{Na}=0.25 \times 2=0.5 \mathrm{ mol}) (inc
(D) 5.6 g of (\mathrm{Na}_3 \mathrm{PO}_4) :
- Molar (\mathrm{Hass}_4 \stackrel{\text{ f }}{=} 3^{\text{f }} \times 23+31+4 \times 16=)
Moles of (\mathrm{Na}=\frac{5.6 \mathrm{ g}}{163 \mathrm{ g} / \mathrm{mol}} \approx 0.0343 \mathrm{ mol})
Conclusion:
- Samples containing the same number of Na atoms: (A) and (B).
Correct option:
(3) A & B are correct.