Question 91. Match List I and List II and select the correct
List I                                List II
(Element)           (Nature element)
A. Sodium              1. Gas
B. Phosphorus      2. Halogen
C. Iodine                3. Alkali metal
D. Radon               4. Transition metal
                               5. Non-metal

Question 92. Match List I and List II and select the correct answer by using the codes given below.
List I (Copper alloys)           List II (Use)
A. Brass                           1. Gears and bearings
B. Bronze                        2. Caps of cartidges
C. Gun metal                  3. Springs and suspension filaments in electrical instruments
D. Phosphor bronze      4. Resistance wire
E. German silver            5. Control valves

Question 93. Assertion (A): Synthetic detergents can lather well in hard water.
Reason (R): Synthetic detergents form soluble calcium and magnesium salts with hard water.

Question 94. Consider the following statements with reference to the periodic table of chemical elements
(a) Ionization potential gradually decreases along a period.
(b) In a group of elements, electron affinity decreases as the atomic weight increases.
(c) In a given period, electro-negativity decreases as the atomic number increases.
Which of these statements(s) is/are correct?

Question 95. Match List I with List II and select the correct
List I (Characteristic)           List II (Particle)
A. 2                               1. Oxidation number of Mn in Mn0₂
B. 3                               2. Oxidation number of S in H₂S₂O₇
C. 4                               3. Oxidation number of Ca in CaO
D. 6                               4. Oxidation number of Al in NaAlH₄

Question 96. With reference to ionic compounds, consider the following statements
(a) Ionic compounds are insoluble in alcohol.
(b) Ionic compounds in the solid state are good conductor of electricity.
Which of these statements is/are correct?

Question 97. Match List I and List II and select the correct answer by using the codes given below.
List I                            List II
A. Magnesium     1. Dolomite
B. Calcium            2. Bauxite
C. Aluminium      3. Limestone
D. Uranium         4. Pitchblende

Question 98. A radioactive substance has a half-life of four months. Three-fourth of the substance would decay in

Question 99. Match List I with List II and select the correct answer by using the codes given below.
List I                             List II
A. Iron               1. Activator of enzymes
B. Magnesium 2. Transfer of electron in photosynthesis
C. Chlorine       3. synthesis of fats
D. Nitrogen      4. synthesis of proteins

Question 100. Assertion (A): A chemical reaction becomes faster at higher temperature.
Reasons (R): At higher temperature molecular motion becomes more rapid.