Metals and Non-metals Past Paper PDF
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This document outlines activities and experiments related to reactions of metals with dilute hydrochloric and nitric acids. It discusses aspects like rate of reaction, temperature changes, and reactivity series. It also explores the concept of aqua regia.
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Metal + Dilute acid → Salt + Hydrogen But do all metals react in the same manner? Let us find out. Activity 3.11 n Collect all the metal samples except sodium and potassium again....
Metal + Dilute acid → Salt + Hydrogen But do all metals react in the same manner? Let us find out. Activity 3.11 n Collect all the metal samples except sodium and potassium again. If the samples are tarnished, rub them clean with sand paper. CAUTION: Do not take sodium and potassium as they react vigorously even with cold water. n Put the samples separately in test tubes containing dilute hydrochloric acid. n Suspend thermometers in the test tubes, so that their bulbs are dipped in the acid. n Observe the rate of formation of bubbles carefully. n Which metals reacted vigorously with dilute hydrochloric acid? n With which metal did you record the highest temperature? n Arrange the metals in the decreasing order of reactivity with dilute acids. Write equations for the reactions of magnesium, aluminium, zinc and iron with dilute hydrochloric acid. Hydrogen gas is not evolved when a metal reacts with nitric acid. It is because HNO3 is a strong oxidising agent. It oxidises the H2 produced to water and itself gets reduced to any of the nitrogen oxides (N2O, NO, NO2). But magnesium (Mg) and manganese (Mn) react with very dilute HNO3 to evolve H2 gas. You must have observed in Activity 3.11, that the rate of formation of bubbles was the fastest in the case of magnesium. The reaction was also the most exothermic in this case. The reactivity decreases in the order Mg > Al > Zn > Fe. In the case of copper, no bubbles were seen and the temperature also remained unchanged. This shows that copper does not react with dilute HCl. Do You Know? Aqua regia, (Latin for ‘royal water’) is a freshly prepared mixture of concentrated hydrochloric acid and concentrated nitric acid in the ratio of 3:1. It can dissolve gold, even though neither of these acids can do so alone. Aqua regia is a highly corrosive, fuming liquid. It is one of the few reagents that is able to dissolve gold and platinum. 3.2.4 How do Metals react with Solutions of other Metal Salts? Activity 3.12 n Take a clean wire of copper and an iron nail. n Put the copper wire in a solution of iron sulphate and the iron nail in a solution of copper sulphate taken in test tubes (Fig. 3.4). n Record your observations after 20 minutes. 44 Science 2024-25
