Positive and Negative Catalysts

Q.

The balanced chemical equation for the reaction of zinc metal with hydrochloric acid is:

1. Zn + HCl → ZnCl + H₂

2. Zn + HCl → ZnCl₂ + H₂

3. Zn + 2HCl → 2ZnCl₂ + H₂

4. Zn + 2HCl → ZnCl₂ + H₂

Q.

Write balanced equation for the reaction between iron and dilute sulphuric acid.

Q.

The catalyst used to reduce the decomposition of hydrogen peroxide is

1. Manganese dioxide

2. Iron

3. Vanadium Pentoxide

4. Phosphoric acid

Q. How is ethyne (acetylene) prepared in the laboratory?

Q.

What are the limitations of a catalyst?

Q.

Iron is a negative catalyst.

1. True

2. False

Q. Give an equation for reaction of ammonical cuprous chloride with ethyne

Q. (a) Name the process used for the manufacture of nitric acid.
(b) What are the reactants required for it and what are their sources?
(c) In which ratio reactants are taken in this process?
(d) Name the catalyst used in the process.
(e) What is the oxidizing agent in this process?
(f) Write the equations involved.

Q. Write balanced equations for the following reactions:
(a) reduction of copper oxide by hydrogen.
(b) reduction of iron (III) oxide by carbon monoxide.
(c) reduction of lead (II) oxide by carbon.

Q. Which of the following factor shifts the reaction,
$PC{l}_3\left(g\right)+C{l}_2\left(g\right)\rightleftharpoons PC{l}_5\left(g\right)+heat$ towards the reactant side?

1. Addition of $PC{l}_5$
2. Increasing the pressure
3. Decreasing the temperature
4. Addition of a catalyst

Q.

Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by the inverting a test tube over it. Then he react the gas with moist Litmus paper. Write a balanced chemical equation for the reaction taking place.

Q.

(a) What is the action of red litmus on:
(i) Dry ammonia gas (ii) Solution of ammonia gas in water

(b)State the observations when ammonium hydroxide is added to the aqueous solution of:
(i) Ferrous sulphate (ii) Aluminium chloride.

Q.

An amylase is a positive catalyst present in saliva which converts starch into maltose.

1. True

2. False

Q. What is a catalyst?

Q.

Match the following catalysts with the process in which they are used:

(a) Vanadium Pentoxide (b) Amylase (c) Iron (d) Phosphoric acid

(i) Biological processes (ii) Manufacture of Sulphuric acid (iii) Manufacture of Ammonia (iv) Reduce the decomposition of Hydrogen Peroxide

1. (a) - (i), (b)- (ii), (c)- (iv) and d- (iii)

2. (a) - (ii), (b)- (i), (c)- (iii) and d- (iv)

3. (a) - (i), (b)- (ii), (c)- (iii) and d- (iv)

4. (a) - (iv), (b)- (iii), (c)- (ii) and d- (i)

Q. Negative catalyst of sulphuric acid

Q.

Making use only of substances chosen from those given below:

Give the equations for the reactions by which you could obtain zinc carbonate (two steps required)

1. 

2. 

3. 

4. 

Q.

Name one lead compound that can be used to oxidise hydrogen chloride to chlorine.

Q. The figure given below illustrates the apparatus used in the laboratory preparation of nitric acid.

(a) Name A (a liquid), B (a solid) and C (a liquid). (Do not give the formulae).
(b) Write an equation to show how nitric acid undergoes decomposition.
(c) Write the equation for the reaction in which copper is oxidized by concentrated nitric acid. [5 MARKS]

Q. A/an ______ is a substance that fasten the rate of a reaction without undergoing any permanent change themselves.

1. metal
2. catalyst
3. halogen
4. isobar

Q. The rate of reaction can be increased by:

1. increasing the amount of negative catalyst
2. decreasing the surface area exposed to the reactant
3. increasing the concentration of the reactant
4. decreasing the temperature of the reaction

Q. Which of the following factors will not disturb the equilibrium state of the reaction? $H_2\left(g\right)+I_2\left(g\right)+heat\rightleftharpoons 2HI\left(g\right)$

1. Change in temperature
2. Addition of catalyst
3. Addition of $H_2$
4. Addition of $I_2$

Q.

(f) Give balanced equations for the following:
(i) Aluminium powder is warmed with hot and concentrated caustic soda solution.
(ii) Preparation of methane from anhydrous sodium ethanoate.
(iii) Calcination of zinc carbonate.
(iv) Plumbo solvency of lead.
(v) Heating of sodium nitrate.

Q.

Manganese dioxide is a type of

1. positive catalyst

2. biological catalyst

3. non- catalyst

4. negative catalyst

Q.

Phosphoric acid is a type of

1. negative catalyst

2. positive catalyst

3. non- catalyst

4. biological catalyst

Q.

A negative catalyst, like iron, decreases the rate of the reaction.

1. False

2. True

Q.

The rate of oxidation of chloroform decreases in the presence of alcohol. Alcohol is a/an ___ for this reaction.

1. Negative Catalyst

2. Electrolyte

3. Positive Catalyst

4. Solvent

Q. Favourable conditions for the $N{H}_3$ formation are high pressure and low temperature.
State whether the statement is True or False

Q.

The following changes represented by letters A, B, C, D can bring about the conversion of iron pyrites (FeS₂) to sulphuric acid (H₂SO₄) in the contact process.
${\mathrm{FeS}}_2\stackrel{A}{\to }{\mathrm{SO}}_2\stackrel{B}{\to }{\mathrm{SO}}_3\stackrel{C}{\to }\mathrm{oleum}\stackrel{D}{\to }{\mathrm{H}}_2{\mathrm{SO}}_4$
(i) Write the balanced equation to show change 'A'.
(ii) Name the above reaction bringing about change 'A'.
(iii) Write the formula of oleum.
(iv) Name the substance C.
(v) What is 'D'? Why is it required?
(vi) State giving reasons, whether 'D' can be used in place of 'C'.

Q. In which of the following equilibrium reactions, the equilibrium would shift to the right if pressure is increased?

1. $N_2+3H_2\leftrightharpoons 2N{H}_3$
2. $H_2+I_2\leftrightharpoons 2HI$
3. $H_2+C{l}_2\leftrightharpoons 2HCl$
4. $N_2+O_2\leftrightharpoons 2NO$