Types of Chemical Reaction

Q.

^{what is effervescence ?}

Q. The diagram shows an experimental set-up for the laboratory preparation of a pungent smelling gas. The gas is alkaline in nature.


(i) Name the gas collected in the jar.
(ii) Write the balanced equation for the above preparation.
(iii) How is the gas being collected?
(iv) Name the drying agent used.
(v) How will you find that the jar is full of gas?

Q.

The chemical reaction between two substances is characterised by a change in colour from orange to green. These two substances are most likely to be :
(a) potassium dichromate solution and sulphur dioxide

(b) potassium permanganate solution and sulphur dioxide

(c) potassium permanganate solution and lemon juice

(d) potassium dichromate solution and carbon dioxide.

Q.

An example of a chemical reaction in which heat is evolved is:

1. Reaction between lead nitrate and potassium iodide

2. Ammonium chloride and Barium hydroxide

3. Reaction between sodium and water

4. Boiling of water

Q.

Identify the substance that is oxidised and the substances that are reduced in the following reactions:

$1.{\mathrm{MnO}}_2+4\mathrm{HCl}\to {\mathrm{MnCl}}_2+2H_{2}O+{\mathrm{Cl}}_{2}2.4\mathrm{Na}+O_2\to 2{\mathrm{Na}}_{2}O3.\mathrm{ZnO}+C\to \mathrm{Zn}+\mathrm{CO}$

Q.

An example of reaction in which gas is evolved is:

1. Burning of magnesium ribbon in air

2. Reaction between limestone and HCl

3. Reaction between Calcium oxide and water

4. Reaction between lead nitrate and potassium iodide

Q. $3Mn{O}_2+4Al\to 3M{n}^{+2}+2A{l}_2{O}_3$
In this reaction, oxidising agent is:

1. $Mn{O}_2$
2. $Al$
3. $A{l}_2{O}_3$
4. $Mn$

Q. Why metals at the top of the reactivity series are never found as free elements.

Q.

How is the rate of a chemical reaction affected by change in temperature? Give an example in support of your answer.

Q. 44. How to find that whether given reaction is double displacement reaction or redox reaction

Q. Write sequential observation for effect of heat on
(a) copper nitrate
(b) lead carbonate
(c) ammonium chloride.

Q.

Which is the correct representation of Hydrolysis?

1. $Salt+Water\to acidic/basicsolution$

2. $Acid+Base\to salt+water$

3. $Compound\stackrel{△}{\to }salt+water$

4. $AB+CD\to AD+CB$

Q. $3{\text{MnO}}_2\left(s\right)+4\text{Al}\left(s\right)\to 3\text{Mn}\left(s\right)+2{\text{Al}}_2{\text{O}}_3\left(s\right)$

In the above reaction, the oxidising agent is:

1. ${\text{MnO}}_2$
2. $\text{Al}$
3. ${\text{Al}}_2{\text{O}}_3$
4. $\text{Mn}$

Q. Why metals at the top of the reactivity series are never found as free elements.

Q. $F{e}_2{O}_3\left(s\right)+3C\left(s\right)\to 4\mathrm{Fe}\left(s\right)+3{\mathrm{CO}}_2\left(s\right)$
The oxidising agent in the given reaction is.

1. $F{e}_2{O}_3$
2. ${\mathrm{CO}}_2$
3. Fe

Q.

The reaction between solutions of silver nitrate and sodium chloride is a precipitation reaction. Explain.

Q. ZnO(s)+CO(g)→Zn(s)+${CO}_2$(g)
In the given reaction, ZnO acts as an oxidising agent.

1. True
2. False