Types of Redox Reactions

Q.

Boojho took some grains of boiled rice in a test tube a and paheli took boiled and chewed rice in a test tube b. both of them poured-1-2-drops of iodine solution into the test tube. What colour change would they have observed. Give reasons for your answer.

Q. During the reaction given below CO + I2O5 → CO2 + I2 What are the equivalent weights of CO and I2O5 if their molar masses are M1 and M2 respectively?

Q.

What do you understand by 'chemical reaction' ?

Q.

Several blocks of magnesium are fixed to the bottom of a ship to

1. Keep away the sharks

2. Make the ship lighter

3. Prevent action of water and salt

4. Prevent puncturing by under-sea rocks

Q.

Iodine gives blue-black colour with

1. Protein

2. Oil

3. Starch

4. Sucrose

Q.

Which one of the following is not a chemical change?

1. Formation of curd

2. Ripening of banana

3. Sublimation of naphthalene

4. Corrosion of photo frame

Q.

What happens when a physical change takes place in a substance?

1. Mass of the substance changes.

2. A new product is formed.

3. Properties like state, colour may change.

4. Chemical composition of a substance changes.

Q. Which of the following metal ions has the greatest tendency to get reduced?

1. Zinc ion
2. Gold ion
3. Copper ion
4. Sodium ion

Q.

State the laws of chemical combination and define each?

Q. When a beam of light is passed through a colloidal solution, it gets:

(A) Reflected
(B) Scattered
(C) Absorbed

Q. Two substances, A and B were made to react to form a third substance, $A_{2}B$ according to the following reaction:
2A + B → $A_{2}B$
Which of the following statements concerning this reaction are correct?
i) The product $A_{2}B$ shows the properties of substances A and B.
ii) Formation of $A_{2}B$ is a chemical change.
iii) The product so formed is a homogenous mixture.
iv) The product so formed cannot be classified as a compound.

A) i and iii
B) i, ii, and iv
C) Only ii

Q. When 3.0 g of carbon is burnt in 8.00 g oxygen, 11.00 g of carbon dioxide is produced.

1. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen?
2. Which law of chemical combinations will govern your answer?

Q. Arrange the following mixtures in the decreasing order of their particle size.
(A) Suspension > Colloid > Solution
(B) Solution > Colloid > Suspension
(C) Solution > Suspension > Colloid
(D) Suspension > Solution > Colloid

Q.

When Lead nitrate is heated it decomposes with a cracking sound, a reddish brown gas is liberated and a solid residue is left in the test tube. What is the pH range of the aqueous solution when the gas is dissolved in water?

Q. If Hg2Cl2 is 100% ionised then its vant hoff factor will be

Q. Burning of wood and rusting of iron bar are examples of ___________ changes.

1. physical
2. chemical
3. physical and chemical
4. biological

Q.

$\text{CaO(s)}+{\text{H}}_2\text{O (l)}\to {\text{Ca(OH)}}_2\text{(aq)}+\text{Heat}$

What can be inferred from the above reaction?

1. The given reaction is exothermic in nature.
2. Water (${\text{H}}_2\text{O})$ is in vapour state.
3. Calcium oxide ($\text{CaO}$) is solid.
4. Calcium hydroxide [${\text{Ca(OH)}}_2$] is aqueous in nature.

Q.

$\text{CaO(s)}+{\text{H}}_2\text{O (l)}\to {\text{Ca(OH)}}_2\text{(aq)}+\text{Heat}$

What can be inferred from the above reaction?

1. The given reaction is exothermic in nature.
2. Calcium oxide ($\text{CaO}$) is solid.
3. Water (${\text{H}}_2\text{O})$ is in vapour state.
4. Calcium hydroxide [${\text{Ca(OH)}}_2$] is aqueous in nature.

Q. Identify the colloid from the following.





(A) Vinegar








(B) Milk







(C) Mud in water

Q.

Milk is a colloid. Select the correct statement regarding milk as colloidal solution.

1. A solid is dispersed in liquid.

2. A gas is dispersed in liquid.

3. A liquid is dispersed in liquid.

4. A liquid is dispersed in solid

Q. Identify the colloid(s) from the following:

(i) Sugar in water

(ii) Smoke in air

(iii) Charcoal in vinegar

(iv) Paint

(A) (i) and (ii)
(B) (ii) and (iv)
(C) Only (ii)
(D) Only (iv)

Q. In the reaction
$3B{r}_2+6C{O}_3^{2-}+3H_{2}O\to 5B{r}^{\ominus }+Br{O}_3^{\ominus }+6HC{O}_3^{\ominus }$
(IIT-JEE, 1996)

1. $B{r}_2$ is oxidised and $C{O}_3^{2-}$ is reduced.
2. $B{r}_2$ is reduced and $H_{2}O$ is oxidised.
3. $B{r}_2$ is neither reduced nor oxidised.
4. $B{r}_2$ is both reduced and oxidised.

Q.

The reaction, $3Cl{O}^{-}\left(aq\right)⟶Cl{O}_3^{-}\left(aq\right)+2C{l}^{-}\left(aq\right)$ is an example of:

1. Oxidation reaction

2. Reduction reaction

3. Disproportionation Reaction

4. Decomposition reaction

Q. Consider the following statements.

Statement 1: The change in which one or more substances lose their identity and form one or more new substances are known as chemical changes.

Statement 2: Process of rolling dough is an example of physical change.

Q. Which of the following is an example for intra-molecular redox reaction?

1. (NH₄)₂Cr₂O₇ → N₂ + Cr₂O₃ + 4 H₂O
2. P₄ + 3 NaOH + 3 H₂O → PH₃ + 3 NaH₂PO₂
3. Ag²⁺ + Ag → 2 Ag⁺⁺
4. 2FeCl₂ + 2HCl + H₂O₂ → 2FeCl₃ + 2H₂O

Q. Who proposed the law of constant proportions?

1. John Dalton
2. Joseph Proust
3. Antoine Lavoisier
4. Ernest Rutherford

Q. Statement 1: No New substance is formed during a physical change.

Statement 2: New substances are formed during chemical changes.

1. Both statements are false.
2. Only statement 1 is true.
3. Only statement 2 is true.
4. Both statements are true.

Q. Which of the following is not a physical change?

1. Cutting of paper
2. Folding of paper
3. Twisting of paper
4. Burning of Paper

Q. For the reaction
$I^{\ominus }+Cl{O}_3^{\ominus }+H_{2}S{O}_4\to C{l}^{\ominus }+HS{O}_4^{-}+I_2$
The correct statement(s) in the balanced equation is/ are:
(IIT-JEE-Advanced 2014)

1. Stoichiometric coefficient of $HS{O}_4^{-}$ is 6.
2. Iodide is oxidized.
3. Sulphur is reduced.
4. $H_{2}O$ is one of the products.

Q. Which of the following is not a physical change?

1. Twisting of paper
2. Burning of Paper
3. Folding of paper
4. Cutting of paper