Question: Which one of the following is not a semiconductor ?

• 1. Si
• 2. Ge
• 3. Se
• 4. Sn

Question: The process of aluminium extraction is called__________________?

• 1. Hall process
• 2. Thermite process
• 3. Haber process
• 4. Contact process

Question: Aqueous solution of borax above 62°C gives crystals of________________?

• 1. Na2B4O7.4H2O
• 2. Na2B4O7.5H2O
• 3. Na2B4O7.2H2O
• 4. Na2B4O7.10H2O

Question: Which of the following is not a use of silicon ?

• 1. Lubricants
• 2. Hydraulic brakes
• 3. Antifreeze
• 4. Water repellent

Question: CO2 is gas while SiO2 is solid at room temperature?

• 1. carbon is non-metal while silicon is semi-metal
• 2. CO2 is an independent molecule while SiO2 has network covalent structure
• 3. CO2 forms multiple bond while silicon does not form multiple bonds
• 4. Silicon has all sigma bonds

Question: Identify the correct statement regarding CO_______________?

• 1. it combines with H2O to form carbonic acid
• 2. it reacts with red blood cells of haemoglobin
• 3. it is powerful oxidizing agent
• 4. it is used to prepare aerated drinks

Question: Boric acid cannot be used__________________?

• 1. As antiseptic in medicine
• 2. For washing eyes
• 3. In soda bottles
• 4. For enamel and glazes

Question: Which element can form tripositive ion ?

• 1. Beryllium
• 2. Carbon
• 3. Silicon
• 4. Aluminium

Question: Which of the following is different with respect to physical appearance ?

• 1. Arsenic
• 2. Phosphorus
• 3. Antimony
• 4. Bismuth

Question: Compounds of nitrogen and phosphorus are mostly________________?

• 1. ionic
• 2. covalent
• 3. polar
• 4. all varieties are possible