Acids, Bases Past Paper PDF

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...

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 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) → Na2ZnO2(s) + H2(g) (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 2.5 n Take two test tubes, label them as A and B. n Take about 0.5 g of sodium carbonate (Na 2CO3) in test tube A and about 0.5 g of sodium hydrogencarbonate (NaHCO3) in test tube B. 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 hydroxide solution) as shown in 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 2CO3 (s) + 2 HCl(aq) → 2NaCl(aq) + H2 O(l) + CO2 (g) Test tube B: NaHCO3 (s) + HCl(aq) → NaCl(aq) + H2O(l) + CO 2 (g) On passing the carbon dioxide gas evolved through lime water, Ca(OH)2 (aq) + CO2 (g) → CaCO3 ( s) + H2 O (l) (Lime water) (White precipitate) 20 Science 2024-25