Question

Practical No. 2
Aim: To identify the type of reaction by studying the reaction and recording the observations,
1. Combustion of magnesium in air
2. Action of dilute sulphuric acid on zinc.
3. To heat lead nitrate,
Apparatus : Beaker, test tubes, pair of tongs, burner, glass rod, etc.
Chemicals : Zinc dust, magnesium strip, lead nitrate powder, dilute sulphuric acid.
Procedure :
Part 1: Combustion of magnesium in air.
1. Hold a piece of magnesium strip on the flame of a burner.
2. Record the observation and write the reaction.
Reaction 1:
2Mg (s) + 0,(s)
2MgO (s)
Observations:
1. The magnesium strip burns with luminous flame.
2. A white coloured powder remains behind.
Number of
Reaction
Number of
products
Interesting feature of
the reaction
Type of the
reaction
reactants
2
2Mg+0 - 2MgO
ute​

Answer 1

Answer:

Aim:-

To identify the type of reactions:-

1. Combustion of magnesium in air
2. Action of dilute sulphuric acid on zinc.
3. To heat lead nitrate.

Materials Required:-

Beaker, test tubes, pair of tongs, burner, glass rod, Zinc dust, magnesium strip, lead nitrate powder, dilute sulphuric acid.

Procedure:-

1. Combustion of magnesium in air

• Take a piece of magnesium ribbon and remove dirt from the surface of the magnesium ribbon by rubbing it with sandpaper.
• With the use of a pair of tongs, hold the magnesium ribbon, ignite the magnesium, and collect the ash from the burned ribbon in a china dish.
• Bring a piece of damp red litmus paper in touch with the MgO's white ash.

2. Action of dilute sulphuric acid on zinc

• Fill a test tube with a 5mL solution of diluted sulfuric acid.
• Add enough zinc granules to it so that the zinc pieces are immersed.
• Put a cork having a delivery tube and a fine jet over the mouth of the test tube immediately.
• Bring a flaming matchstick up to the fine jet's mouth.

3. To heat lead nitrate

• In a boiling tube, add 2 g of white lead nitrate powder.
• Using a tong, warm the boiling tube over the burner's heat.
• Observe what occurs as the lead nitrate is heated in the boiling tube.

Observations:-

1. Combustion of magnesium in air

• Magnesium is a silvery-white metal that burns in the air and produces magnesium oxide by combining with atmospheric oxygen.

• $2MgO(s)$
• Red litmus paper becomes blue when exposed to magnesium oxide. This reaction demonstrates the basic nature of magnesium oxide.

2. Action of dilute sulphuric acid on zinc

• A brisk response may be seen, with gas bubbles emerging.
• The gas emitted by the jet burns instantly, accompanied by a pop sound or a minor explosion, confirming the presence of hydrogen gas.

3. To heat lead nitrate

• Brown vapors are released (brown fumes coming out of the test tube).
• After heating, the white lead nitrate changed into a dark powder.

Inferences:-

1. Combustion of magnesium in air

• The interaction between the two elements magnesium and oxygen results in the creation of magnesium oxide.
• Magnesium oxide is distinct from the reactants magnesium and oxygen.

2. Action of dilute sulphuric acid on zinc

• Zinc metal is more reactive than hydrogen.
• Zinc reacts with diluted sulfuric acid to form zinc sulphate and hydrogen gas.
• A pop sound is produced when hydrogen gas burns.

3. To heat lead nitrate

• The dark gases emanating from the boiling tube are nitrogen dioxide.
• When the white lead nitrate is heated, lead oxide is produced as a brown powder.

Results:-

1. Combustion of magnesium in air

It is a type of combination reaction.

• $2Mg(s) +O_{2} (g)$ ⇒ $2MgO(s)$

2. Action of dilute sulphuric acid on zinc

It is a type of displacement reaction

$Zn + H_{2}SO_{4}$ ⇒ $ZnSO_{4} + H_{2}$

3. To heat lead nitrate

It is a type of decomposition reaction.

$2Pb(NO_{3})_{2}$ ⇒ $2PbO +4 NO_{2}+O_{2}$

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