The following are some well-known abbreviations, which have been used in this chapter. Expand each one to its full form:
(a) MALT (b) CMI (c) AIDS (d) NACO (e) HIV

Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows. Use the Table above to answer the following questions about metals A, B, C and D. (i) Which is the most reactive metal? (ii) What would you observe if B is added to a solution of Copper(II) sulphate? (iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.

Using divisibility tests, determine which of the following numbers are divisible by 2 (a) 2144 (b) 1258 (c ) 4336 (d) 633 (e ) 1352

Using divisibility determine which of the following numbera are divisible by 5 (a) 438750 (b) 179015 (c ) 125 (d) 639210 (e ) 17852

Which of following metal is extracted by the electrolysis of its salt in molten state (a) Na, (b) Mg, (c) Al, (d) Fe, (e) Ag The correct answer is

Given below are some examples of wave motion. Statein each case if the wave motion is transverse, longitudinal or a combinatin of both. (a) Motion of kink in a longitudinal spring produced by displacing one end of the spring sideways. (b) Waves produced in a cylinder containing a liquid by moving its piston back and forth. (c ) Waves produced by a motorboat sailing in water. (d) Ultrasonic waves in air produced by a vibrating quartz crystal.