Balancing Redox Reaction

Q.

What is formality? Explain with example.

Q. A given solution of $H_{2}S{O}_4$ is labelled as 49% (w/w), then the correct statement regarding the solution is $(d=1.3\text{g/mL})$

1. $m=\frac{500}{51}$
2. $N=\frac{1000}{51}$
3. $\%\text{w/v}=(49\times 1.3)\%$
4. $M=6.5$

Q. How many electrons are lost or gained by Cr in the given chemical reaction below:
$C{r}_2{O}_7^{2-}\to C{r}^{3+}$

1. 5
2. 4
3. 2
4. 6

Q.

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

1. 1.78 F

2. 16 F

3. 0.17 F

4. 1.7 F

Q. Calculate the volume of $0.1$ M $HCl$ required to react completely with $1$ g of a equimolar mixture of $N{a}_{2}C{O}_3$ and $NaHC{O}_3$.

1. 15.78 mL
2. 187.8 mL
3. 200 mL
4. 157.8 mL

Q. The density of 3M solution of $N{a}_2{S}_2{O}_3$ is $1.25$ g mL${}^{-1}$. Calculate, the $\%$ by weight of $N{a}_2{S}_2{O}_3$.

1. 38%
2. 50%
3. 11%
4. 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?

1. 70 mL
2. 200 mL
3. 450 mL
4. 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 ___.

1. 250 ppm
2. 200 ppm
3. 400 ppm
4. 1000 ppm

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

1. 0.65
2. 0.95
3. 0.32
4. 1.68

Q. A given solution of $H_{2}S{O}_4$ is labelled as 49% (w/w), then the correct statement regarding the solution is $(d=1.3\text{g/mL})$

1. $m=\frac{500}{51}$
2. $N=\frac{1000}{51}$
3. $\%\text{w/v}=(49\times 1.3)\%$
4. $M=6.5$

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

1. 6.85 g
2. 3.85 g
3. 5.82 g
4. 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:

1. $176.5$
2. $252.2$
3. $287.6$
4. $360.1$

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?

1. 70 mL
2. 200 mL
3. 450 mL
4. 350 mL

Q. Isopropyl alcohol $C_3{H}_8$, 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. 1:2
2. 2:1
3. 2:3
4. 3:2

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

1. $72.5$
2. $65$
3. $62.5$
4. $\text{N}one$

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?

1. 330
2. 316
3. 32
4. 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 ___.

1. 8.57 %
2. 15.32 %
3. 12.25 %
4. 9.51 %

Q. How many electrons are lost or gained by Cr in the given chemical reaction below:
$C{r}_2{O}_7^{2-}\to C{r}^{3+}$

1. 5
2. 4
3. 2
4. 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?

1. 7555L

2. 1586.6L

3. 850L

4. 5745.5L

Q. The density of $3M$ solution of $N{a}_2{S}_2{O}_3$ is $1.25gm{L}^{-1}$. Calculate, the molalities of $N{a}^{+}$ and $S_2{O}_3^{2-}$ ions respectively.

1. 7.732 and 3.865
2. 3.865 and 7.732
3. 5.643 and 4.321
4. None of the above

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

1. 0.37
2. 0.4
3. 0.22
4. 0.51

Q. 50 ml of $H_2{O}_2$ solution when titrated with 0.1 M $KMn{O}_4$ solution in acidic medium, volume required is 40 ml. Volume strength of $H_2{O}_2$ solution is

1. 11.2
2. 22.4
3. 1.12
4. 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 ___.

1. 8.57 %
2. 15.32 %
3. 12.25 %
4. 9.51 %

Q. Calculate the volume of $0.1$ M $HCl$ required to react completely with $1$ g of a equimolar mixture of $N{a}_{2}C{O}_3$ and $NaHC{O}_3$.

1. 15.78 mL
2. 187.8 mL
3. 200 mL
4. 157.8 mL

Q. Solution(s) containing 30 g $C{H}_{3}COOH$ is/are:

1. 50 g of 70% (w/v) $C{H}_{3}COOH$ solution
   $[d_{sol}=1.4g/mL]$
2. 50 g of 10 M $C{H}_{3}COOH$ solution
   $[d_{sol}=1g/mL]$
3. 50 g of 60% (w/w) $C{H}_{3}COOH$ solution
   $[d_{sol}=1.4g/mL]$
4. 50 g of 10 m $C{H}_{3}COOH$ solution
   ​​

Q. $\underset{–}{X}KMn{O}_4+\underset{–}{Y}{K}_2{C}_2{O}_4+\underset{–}{Z}{H}_{2}S{O}_4\to \underset{–}{A}Mn{0}_4+\underset{–}{B}C{0}_2+6K_{2}S{O}_4+\underset{–}{S}{H}_{2}O$
X, Y, Z, A, B and S are stoichiometric coefficients.
Here X, Y, Z, A and B are respectively

1. 2, 5, 8, 2, 10
2. 2, 4, 9, 4, 10
3. 5, 9, 12, 4, 10
4. None of these

Q. A sea water sample contains $8\times {10}^{-3}$ g of dissolved oxygen per kilogram. What is the concentration of oxygen in parts per billion?

1. $8ppb$
2. $8\times {10}^{-3}ppb$
3. $8000ppb$
4. $800ppb$

Q. $\underset{–}{X}KMn{O}_4+\underset{–}{Y}{K}_2{C}_2{O}_4+\underset{–}{Z}{H}_{2}S{O}_4\to \underset{–}{A}Mn{0}_4+\underset{–}{B}C{0}_2+6K_{2}S{O}_4+\underset{–}{S}{H}_{2}O$
X, Y, Z, A, B and S are stoichiometric coefficients.
Here X, Y, Z, A and B are respectively

1. 2, 5, 8, 2, 10
2. 2, 4, 9, 4, 10
3. 5, 9, 12, 4, 10
4. None of these

Q. 50 ml of $H_2{O}_2$ solution when titrated with 0.1 M $KMn{O}_4$ solution in acidic medium, volume required is 40 ml. Volume strength of $H_2{O}_2$ solution is

1. 11.2
2. 22.4
3. 1.12
4. 2.24

Q. $A{s}_2{S}_3+xN{O}_3^{-}+y{H}^{+}\to 2As{O}_4^{3-}+zN{O}_2+aS+2H_{2}O$ Here $x,y,z$ and $a$ respectively are

1. 10, 4, 10, 3
2. 5, 4, 5, 3
3. 4, 10, 3, 10
4. None of these