Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is __________ × 10^-1 M. (Nearest integer)

[Atomic mass : Na = 23.0, O = 16.0, H = 1.0]

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Vishal Baghel | Contributor-Level 10

a month ago

$N a_{2} O + H_{2} O \to 2 N a O H$

w = 20 g

$V_{H_{2} O} = 500 m L$

Mole of Na₂O= $\frac{20}{62}$

$?$ 1 mole of Na₂O gives 2 mole of NaOH

$∴ (\frac{20}{62})$ mole of Na₂O gives $(2 \times \frac{20}{62})$ moles of NaOH

$= \frac{20}{31} m o l e$

Molarity of NaOH solution

$= \frac{\frac{20}{31} \times 100}{500} M = \frac{20}{31} \times 2 M = \frac{40}{31} M$

= 1.29 M

= $12.9 \times 1 0^{- 1} M \approx 13 \times 1 0^{- 1} M$

Ans. = 13

<math> <mrow> <mi>N</mi> <msub> <mrow> <mi>a</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msub> <mi>O</mi> <mo>+</mo> <msub> <mrow> <mi>H</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msub> <mi>O</mi> <mo>→</mo> <mn>2</mn> <mi>N</mi> <mi>a</mi> <mi>O</mi> <mi>H</mi> </mrow> </math> w = 20 g <math> <mrow> <msub> <mrow> <mi>V</mi> </mrow> <mrow> <msub> <mrow> <mi>H</mi> </mrow> <mrow> <mn>2</mn> </mrow> </msub> <mi>O</mi> </mrow> </msub> <mo>=</mo> <mn>5</mn> <mn>0</mn> <mn>0</mn> <mi>m</mi> <mi>L</mi> </mrow> </math>        Mole of Na2O=   <math> <mrow> <mfrac> <mrow> <mn>2</mn> <mn>0</mn> </mrow> <mrow> <mn>6</mn> <mn>2</mn> </mrow> </mfrac> </mrow> </math> <math> <mrow> <mo>?</mo> </mrow> </math> 1 mole of Na2O gives 2 mole of NaOH <math> <mrow> <mo>∴</mo> <mrow> <mo>(</mo> <mrow> <mfrac> <mrow> <mn>2</mn> <mn>0</mn> </mrow> <mrow> <mn>6</mn> <mn>2</mn> </mrow> </mfrac> </mrow> <mo>)</mo> </mrow> </mrow> </math> mole of Na2O gives <math> <mrow> <mrow> <mo>(</mo> <mrow> <mn>2</mn> <mo>×</mo> <mfrac> <mrow> <mn>2</mn> <mn>0</mn> </mrow> <mrow> <mn>6</mn> <mn>2</mn> </mrow> </mfrac> </mrow> <mo>)</mo> </mrow> </mrow> </math> moles of NaOH <math> <mrow> <mo>=</mo> <mfrac> <mrow> <mn>2</mn> <mn>0</mn> </mrow> <mrow> <mn>3</mn> <mn>1</mn> </mrow> </mfrac> <mi>m</mi> <mi>o</mi> <mi>l</mi> <mi>e</mi> </mrow> </math>    Molarity of NaOH solution <math> <mrow> <mo>=</mo> <mfrac> <mrow> <mfrac> <mrow> <mn>2</mn> <mn>0</mn> </mrow> <mrow> <mn>3</mn> <mn>1</mn> </mrow> </mfrac> <mo>×</mo> <mn>1</mn> <mn>0</mn> <mn>0</mn> </mrow> <mrow> <mn>5</mn> <mn>0</mn> <mn>0</mn> </mrow> </mfrac> <mi>M</mi> <mo>=</mo> <mfrac> <mrow> <mn>2</mn> <mn>0</mn> </mrow> <mrow> <mn>3</mn> <mn>1</mn> </mrow> </mfrac> <mo>×</mo> <mn>2</mn> <mi>M</mi> <mo>=</mo> <mfrac> <mrow> <mn>4</mn> <mn>0</mn> </mrow> <mrow> <mn>3</mn> <mn>1</mn> </mrow> </mfrac> <mi>M</mi> </mrow> </math> = 1.29 M=  <math> <mrow> <mn>1</mn> <mn>2</mn> <mo>.</mo> <mn>9</mn> <mo>×</mo> <mn>1</mn> <msup> <mrow> <mn>0</mn> </mrow> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> <mi>M</mi> <mo>≈</mo> <mn>1</mn> <mn>3</mn> <mo>×</mo> <mn>1</mn> <msup> <mrow> <mn>0</mn> </mrow> <mrow> <mo>−</mo> <mn>1</mn> </mrow> </msup> <mi>M</mi> </mrow> </math> Ans. = 13

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Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is __________ × 10^-1 M. (Nearest integer)

[Atomic mass : Na = 23.0, O = 16.0, H = 1.0]

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Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is __________ × 10-1 M. (Nearest integer) [Atomic mass : Na = 23.0, O = 16.0, H = 1.0]

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Sodium oxide reacts with water to produce sodium hydroxide. 20.0 g of sodium oxide is dissolved in 500 mL of water. Neglecting the change in volume, the concentration of the resulting NaOH solution is __________ × 10^-1 M. (Nearest integer)

[Atomic mass : Na = 23.0, O = 16.0, H = 1.0]