Reaction of Metals with Oxygen (Burnt in Air)

Q.

Why should a magnesium ribbon be cleaned before burning in air?

Q. Why is magnesium ribbon cleaned with sandpaper before burning it in air?

Q.

Questions 12(c)

Give reason why aluminium is a highly reactive metal, yet it is used to make utensils for cooking?

Q.

Why should magnesium ribbon be cleaned before burning in air ?

Q.

What will happen when metals react with water?

Q.

Question 12 (b)

Give reason why sodium, potassium and lithium are stored in oil?

Q.

An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be:

1. Calcium

2. Silicon

3. Carbon

4. Iron

Q.

Give a reason for the following:

Sodium and potassium are stored in kerosene.

Q.

Why magnesium and calcium don't react with cold water?

Q.

Write balanced equation for action of heat on copper nitrate?

Q.

The metal whose salts are sensitive to light is?

1. Zinc

2. Silver

3. Copper

4. Aluminum

Q.

Metals react with oxygen in air to form _________.

1. Carbonates

2. Oxides

3. Sulphides

4. Nitrates

Q. A magnesium ribbon is burnt in oxygen to give a white compound 'X' accompanied by emission of light. If the burning ribbon is now placed in an atmosphere of nitrogen, it continues to burn and forms a compound 'Y'. Write a balanced chemical equation when 'X' is dissolved in water.

1. $2Mg+O_2\to 2MgO$
2. $3Mg+N_2\to M{g}_3{N}_2$
3. $Mg+H_{2}O\to Mg(OH{)}_2$
4. $MgO+H_{2}O\to Mg(OH{)}_2$

Q.

How is ${\mathrm{NH}}_4^{+}$ formed?

Q.

What happens when zinc combines with steam?

Q. Give reasons for the following:
(i) Sodium is more reactive than aluminium.
(ii) Mercury is not the only metallic liquid at around 30 C.
(iii) Metals always combine by electrovalency.
(iv) Metal ions are always positively charged.
(v) Metal ions always get discharged at the cathode during electrolysis.
(vi) Metals generally do not form hydrides.
(vii) Metals are always monoatomic.
(viii) Sodium and potassium cannot be kept exposed to air.
(ix) Sodium and potassium should not be treated with acids.
(x) Hydrogen is not a metal but it has been assigned a place in the reactivity series of metals.

Q.

In general, when metal oxides react with water, the resulting solution may be called as:

1. Neutral

2. Basic

3. Acidic

4. Coloured

Q.

An element A which is a part of common salt and kept under kerosene reacts with another element B of atomic number 17 to give a product C. When an aqueous solution of product C is electrolysed then a compound D is formed and two gases are liberated.
(a) What are A and B?
(c) Identify C and D.
(c) What will be the action of C on a litmus solution? Why?
(d) State whether element B is a solid, liquid or gas at room temperature.
(e) Write the formula of the compound formed when element B reacts with an element E having atomic number 5.

Q.

Metals react with oxygen in air to form _________.

1. Oxides

2. Carbonates

3. Sulphides

4. Nitrates

Q.

A metal X reacts with oxygen to form a compound which possess high melting point. The compound is also soluble in water. The element X is:

1. Calcium
2. Carbon
3. Silicon
4. Sulphur

Q. Why alkali metals are good reducing agents?

Q. Name two metals which do not react with oxygen.

Q.

Differentiate among acidic oxides, basic oxides, amphoteric oxides and neutral oxides.

Q. Which of the following metals on reacting with oxygen forms an amphoteric oxide?

1. Na (Sodium)
2. Al (Aluminium)
3. C (Carbon)
4. K (Potassium)

Q.

A metal with shining appearance reacts with hot water and also with dilute hydrochloric acid evolving hydrogen gas. Suggest giving reasons why this metal cannot be copper.

Q. Arrange the given metals in the order of increasing reactivity towards oxygen: $Mg,Cu,K,Na$

1. $Cu<Mg<Na<K$
2. $Cu<Mg<K<Na$
3. $Mg<Cu<Na<K$
4. $Cu<K<Na<Mg$

Q.

what happens when potassium and sodium reacts with water ?

Q. Identify X and Y in the following chemical reaction.

$\text{NaOH(aq)}+\text{X}\to {\text{Na}}_2{\text{ZnO}}_2\text{(aq)}+\text{Y}$

1. X is Na and Y is hydrogen.
2. X is Cu and Y is water.
3. X is Zn and Y is water.
4. X is Zn and Y is hydrogen.

Q.

Question 42
An element is placed in 2nd Group and 3rd Period of the Periodic Table, burns in presence of oxygen to form a basic oxide.

(a) Identify the element.

(b) Write the electronic configuration.

(c) Write the balanced equation when it burns in the presence of air.

(d) Write a balanced equation when this oxide is dissolved in water.

(e) Draw the electron dot structure for the formation of this oxide.

Q.

Give reason: Aluminium is a highly reactive metal, yet it is used for cooking.