# Balancing Redox Reaction

## Trending Questions

**Q.**

What is formality? Explain with example.

**Q.**A given solution of H2SO4 is labelled as 49% (w/w), then the correct statement regarding the solution is (d=1.3 g/mL)

- m=50051
- N=100051
- %w/v=(49×1.3)%
- M=6.5

**Q.**How many electrons are lost or gained by Cr in the given chemical reaction below:

Cr2O2−7→Cr3+

- 5
- 4
- 2
- 6

**Q.**

Calculate the formality of NaCl solution having 1.78 gm solute dissolved in 178 ml solution.

1.78 F

16 F

0.17 F

1.7 F

**Q.**Calculate the volume of 0.1 M HCl required to react completely with 1 g of a equimolar mixture of Na2CO3 and NaHCO3.

- 15.78 mL
- 187.8 mL
- 200 mL
- 157.8 mL

**Q.**The density of 3M solution of Na2S2O3 is 1.25 g mL−1. Calculate, the % by weight of Na2S2O3.

- 38%
- 50%
- 11%
- 98%

**Q.**Alcohol is commonly used as a hand sanitizer and as an antiseptic for small cuts. It is sold as 70 % (v/v) solution of isopropyl alcohol in water. What volume of isopropyl alcohol is used to make 500 mL of rubbing alcohol?

- 70 mL
- 200 mL
- 450 mL
- 350 mL

**Q.**A 500 g toothpaste sample has 0.2 g of fluoride. The concentration of fluoride ions in terms of ppm level is ___.

- 250 ppm
- 200 ppm
- 400 ppm
- 1000 ppm

**Q.**Find the mole fraction of water present in 3 molal aqueous solution of NaOH.

- 0.65
- 0.95
- 0.32
- 1.68

**Q.**A given solution of H2SO4 is labelled as 49% (w/w), then the correct statement regarding the solution is (d=1.3 g/mL)

- m=50051
- N=100051
- %w/v=(49×1.3)%
- M=6.5

**Q.**What is the mass of KI in 14.86 mL of a 32.44 g/100 mL aqueous KI solution?

- 6.85 g
- 3.85 g
- 5.82 g
- 4.82 g

**Q.**Cortisone is a molecular substance that has 21 atoms of carbon per molecule. The mass percentage of carbon in cortisone is 69.98%. Its molar mass is:

- 176.5
- 252.2
- 287.6
- 360.1

**Q.**Alcohol is commonly used as a hand sanitizer and as an antiseptic for small cuts. It is sold as 70 % (v/v) solution of isopropyl alcohol in water. What volume of isopropyl alcohol is used to make 500 mL of rubbing alcohol?

- 70 mL
- 200 mL
- 450 mL
- 350 mL

**Q.**Isopropyl alcohol C3H8, also known as rubbing alcohol, is an alcoholic mixture intended for external use as antiseptic. If the two different companies A and B are manufacturing rubbing alcohol of concentrations 47% (v/v) and 23.5% (v/v) respectively from isopropyl alcohol of density x g/mL, find the ratio of mass of isopropyl alcohol present in equal volumes of rubbing alcohol A and B.

- 1:2
- 2:1
- 2:3
- 3:2

**Q.**A 300 g, 30% (w/w) NaOH solution is mixed with 500 g 40% (w/w) NaOH solution. What is % (w/v) NaOH, If density of final solution is 2 g/ml.

- 72.5
- 65
- 62.5
- None

**Q.**What volume (in mL) of a 45% (v/v) acid solution of a monoprotic strong acid must be mixed with a 20% (v/v) solution of the same acid to produce 800 mL of a 29.875% (v/v) acid solution?

- 330
- 316
- 32
- 325

**Q.**When 400 g of a 20 % solution by weight was cooled, 50 g of the solute precipitates. The percentage concentration of the remaining solution is ___.

- 8.57 %
- 15.32 %
- 12.25 %
- 9.51 %

**Q.**How many electrons are lost or gained by Cr in the given chemical reaction below:

Cr2O2−7→Cr3+

- 5
- 4
- 2
- 6

**Q.**

What volume of air containing 21% of oxygen by volume is required to completely burn one kg of carbon that contains 15% of non-combustible substance?

7555L

1586.6L

850L

5745.5L

**Q.**The density of 3 M solution of Na2S2O3 is 1.25 g mL−1. Calculate, the molalities of Na+ and S2O2−3 ions respectively.

- 7.732 and 3.865
- 3.865 and 7.732
- 5.643 and 4.321
- None of the above

**Q.**A mixture of carbon monoxide and carbon dioxide is found to have a density of 1.7 g/L at stp(atm). The mole fraction of carbon monoxide is

- 0.37
- 0.4
- 0.22
- 0.51

**Q.**50 ml of H2O2 solution when titrated with 0.1 M KMnO4 solution in acidic medium, volume required is 40 ml. Volume strength of H2O2 solution is

- 11.2
- 22.4
- 1.12
- 2.24

**Q.**When 400 g of a 20 % solution by weight was cooled, 50 g of the solute precipitates. The percentage concentration of the remaining solution is ___.

- 8.57 %
- 15.32 %
- 12.25 %
- 9.51 %

**Q.**Calculate the volume of 0.1 M HCl required to react completely with 1 g of a equimolar mixture of Na2CO3 and NaHCO3.

- 15.78 mL
- 187.8 mL
- 200 mL
- 157.8 mL

**Q.**Solution(s) containing 30 g CH3COOH is/are:

- 50 g of 70% (w/v) CH3COOH solution

[dsol=1.4g/mL] - 50 g of 10 M CH3COOH solution

[dsol=1g/mL] - 50 g of 60% (w/w) CH3COOH solution

[dsol=1.4g/mL] - 50 g of 10 m CH3COOH solution

**Q.**X––KMnO4+Y––K2C2O4+Z––H2SO4→A––Mn04+B––C02+6K2SO4+S––H2O

X, Y, Z, A, B and S are stoichiometric coefficients.

Here X, Y, Z, A and B are respectively

- 2, 5, 8, 2, 10
- 2, 4, 9, 4, 10
- 5, 9, 12, 4, 10
- None of these

**Q.**A sea water sample contains 8×10−3 g of dissolved oxygen per kilogram. What is the concentration of oxygen in parts per billion?

- 8 ppb
- 8×10−3ppb
- 8000 ppb
- 800 ppb

**Q.**X––KMnO4+Y––K2C2O4+Z––H2SO4→A––Mn04+B––C02+6K2SO4+S––H2O

X, Y, Z, A, B and S are stoichiometric coefficients.

Here X, Y, Z, A and B are respectively

- 2, 5, 8, 2, 10
- 2, 4, 9, 4, 10
- 5, 9, 12, 4, 10
- None of these

**Q.**50 ml of H2O2 solution when titrated with 0.1 M KMnO4 solution in acidic medium, volume required is 40 ml. Volume strength of H2O2 solution is

- 11.2
- 22.4
- 1.12
- 2.24

**Q.**As2S3+xNO−3+yH+→2AsO3−4+zNO2+aS+2H2O Here x, y, z and a respectively are

- 10, 4, 10, 3
- 5, 4, 5, 3
- 4, 10, 3, 10
- None of these