Page 25 - NCERT Science Class 10 English Medium

Note that the metal in the above reactions displaces hydrogen atoms
from the acids as hydrogen gas and forms a compound called a salt.
Thus, the reaction of a metal with an acid can be summarised as –
Acid + Metal → Salt + Hydrogen gas

Can you now write the equations for the reactions you have observed?

Activity 2.4
Activity
Activity 2.4
Activity 2.42.4
Activity 2.4
n Place a few pieces of granulated zinc metal in a test tube.
n Add 2 mL of sodium hydroxide solution and warm the contents
of the test tube.
n Repeat the rest of the steps as in Activity 2.3 and record your
observations.

The reaction that takes place can be written as follows.
2NaOH(aq) + Zn(s) → Na ZnO (s) + H (g)
2 2 2
(Sodium zincate)

You find again that hydrogen is formed in the reaction. However,
such reactions are not possible with all metals.

2.1.3 How do Metal Carbonates and Metal
Hydrogencarbonates React with Acids?
Activity 2.52.5
Activity
Activity 2.5
Activity
2.5
Activity 2.5
n Take two test tubes, label them as A
and B.
n Take about 0.5 g of sodium carbonate
(Na CO ) in test tube A and about
2 3
0.5 g of sodium hydrogencarbonate
(NaHCO ) in test tube B.
3
n Add about 2 mL of dilute HCl to both
the test tubes.
n What do you observe?
n Pass the gas produced in each case
through lime water (calcium
Figure 2.2
Figure 2.2
Figure 2.2
Figure 2.2 hydroxide solution) as shown in
Figure 2.2
Passing carbon dioxide gas Fig. 2.2 and record your observations.
through calcium hydroxide
solution
The reactions occurring in the above Activity are written as –
Test tube A: Na CO (s) + 2 HCl(aq) → 2 Na Cl(aq) + H O(l) + CO (g)
2 3 2 2
Test tube B: NaHCO (s) + HCl(aq) → Na Cl(aq) + H O(l) + CO (g)
3 2 2
On passing the carbon dioxide gas evolved through lime water,
(
)
Ca(OH) (aq) + CO (g) → CaCO s + H O(l)
2 2 3 2
(Lime water) (White precipitate)
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