Which of the following statements about phosphorus is NOT correct?
- A. Phosphorus is a solid mineral
- B. Phosphorus is obtained by oxidation reaction of phosphate
- C. Phosphorus exists in two allotropic forms
- D. Both forms of phosphorus are interconvertible
- E. Yellow phosporus ignites when rubbed on a rough surface
Fats and oils are?
- A. addition products of long chain fatty acids and alkali
- B. addition products of long-chain fattyy acids and glycerol
- C. condensation products of long-chain fatty acids and glycerol
- D. condensation products of formaldehyde and glycerol
- E. liquids at 20°C
When air is compressed?
- A. its density decreases
- B. it solidifies
- C. its temperature decreases
- D. its temperature increases
- E. its temperature remains unchanged
If an organic compound decolorizes bromine water then the compound is?
- A. saturated
- B. supersaturated
- C. unsaturated
- D. a solid
- E. protonated
When sodium nitrate dissolves in water, ∆H is positive. This means that?
- A. the reaction is catalysed
- B. the reaction is complete
- C. the reaction is exothermic
- D. the reaction is endthermic
- E. sodium nitrate is highly soluble in water
Na2CO3 + 2HCI → 2NaCI + H2O + CO2. Using the above equation, what volume of carbondioxide, measured at s.t.p is liberated when 53g of sodium carbonate is dissolved in hydrochloric acid?
(1 mole of gas occupies 22.4 dm3 at s.t.p)
(Na = 23, C = 12, O = 16)
- A. 44.8 dm3
- B. 11.2 dm3
- C. 100.1 dm3
- D. 3.0 dm3
- E. 22.4 dm3
In the reaction of oxygen with hydrogen to produce water, which of the following statements is true?
- A. One atom of hydrogen reacts with two atoms of oxygen to give one molecule of water
- B. Two atoms of hydrogen react with two atoms of oxygen to give two molecules of water
- C. One molecule of oxygen reacts with one molecule of hydrogen to give two molecules of water
- D. One molecule of hydrogen reaccts with two molecules of oxygen to give three molecules of water
- E. One molecule of oxygen reacts with two molecules of hydrogen to give two molecules of water
Which of the following is the electronic configuration of sodium?
(Atomic number of Na = 11)
- A. 1s2 2s22p6 3s2
- B. 1s2 2s22p6 3s2 3p1s2 2s22p6 3s1
- C. 1s2 2s22p6 3s1
- D. 1s2 2s22p6 3s°
- E. 1s2 2s22p6 4s1
A polymerization reaction is one in which?
- A. small molecules form giant molecules
- B. atoms form molecules
- C. giant molecules form small molecules
- D. molecules form volatile compounds
- E. a molecule rearranges itself
Allotropes are elements having?
- A. different physical but the same chemical properties
- B. different chemical but the same physical properties
- C. the same chemical and physical properties
- D. different atomic structure
- E. the same position in the periodic table
Which of the following can have an isomer?
- A. C2H4
- B. C4H10
- C. C3H8
- D. C2H6
- E. C6H6
In the preparation of ammonia, which of the following is used as the drying agent?
- A. CaO
- B. CaCI2
- C. Conc. H2SO4
- D. P2O5
- E. H3PO4
Which of the following processes takes place during electrolysis?
- A. Positive ions are discharged at the anode bby gaining sufficient electrons to become neutral
- B. Negative ions are dicharged at the anode by gaining suficient electrons to become neutral
- C. Positive ions are discharged at the anode by losing sufficient electrons to become neutral
- D. Negative ions are discharge at the anode by losing sufficient electrons to become neutral
- E. Nothing happens
The brown coloration in nitric acid prepared in the laboratory can be removed by?
- A. heating the acid
- B. bubbling air through the acid
- C. cooling the acid
- D. adding a decolorizing agent
- E. adding a base
In the reaction
C + 2HNO3 → CO2 + NO2 + NO + H2O nitric acid is acting as?
- A. a reducing agent
- B. a nitrating agent
- C. an oxidizing agent
- D. a catalytic agent
- E. a neutralizing agent
If concentrated sulphric acid is added to sugar and warmed gently, the sugar changes from white to brown and finally to a black mas of carbon. In this reaction, concentrated sulphuric acid is acting as ?
- A. a drying agent
- B. an oxidizing agent
- C. a dehydrated agent
- D. a reducing agent
- E. a hydrolysing agent
Which of the following statements is NOT true of electrovalent compounds?
- A. They are solids
- B. They do not vaporized easily
- C. They usually dissolve in water
- D. The elements forming the compounds normally have their valency electrons in a shared state
- E. They conduct electricity
the number of atoms in one mole of a substance is equal to?
- A. the atomic number
- B. the avogadro number
- C. the gas constant
- D. the number of neutrons
- E. the number of electrons
Oxidation is the process of?
- A. gain of electrons
- B. loss of electrons
- C. gain of hydrogen
- D. loss of oxygen
- E. addition of an electropositive element to a substance
Sodium and potassium belong to the same group of the Periodic Table. This is because?
- A. both are metals
- B. both are soft and lighter than water
- C. both form cations by losing electrons
- D. both have identical electronic configuration
- E. both react with water vigorously
The mass number of an atom is?
- A. the number of electrons in the atom
- B. the number of protons in the nucleus of the atom
- C. the number of neutrons in the nucleus of the atom
- D. the sum of numbers of electrons and protons inthe atom
- E. the sum of numbers of proton and neutrons in the nucleus of the atom