Explain the following :
(a) It is easier to cut with a sharp knife than with a blunt one.
(b) Sleepers are laid below the rails.

Explain the following: (a) More metal fluorides are ionic in nature than metal chlorides. (b) Perchloric acid is a stronger acid than sulphuric acid. (c ) Fluorine does not undergo disproportionation reactions but other halogens do.

Explain the following terms with one example each. (a) Corrosion (b) Rancidity

Explain the following : (a) NO_(2) readily forms a dimer. (b) BiCI_(3) is more stable than BiCI_(5).

Explain the following : (a) The electron gain enthalpy with negative sign for fluorine is less than for chlorine, still fluorine is a stronger oxidising agent than chlorine. (b) XeF_(2) is linear molecule without a bend. (c) NCl_(3) is an endothermic compound while NF_(3) is an exothermic one.

Explain the following : (a) The dipole moment of chlorobenzone is lower than that of cyclohexyl chloride. (b) Alkyl halides, though polar, are immiscible with water. (c) Grignard reagents should be prepared under anhydrous condition.

B has a smaller first ionization enthalpy than Be. Consider the following statements (i) it is easier to remove 2p electron than 2s electron (ii) 2p electron of B is more shielded from the nucleus by the inner core of electrons than the 2s electrons of Be (iii) 2s electron has more penetration power than 2p electron (iv) atomic radius of B is more than Be (atomic number B= 5, Be = 4) The correct statements are

Which of the following statements is incorrect? A. a cricketer moves his hands backwards while holding a catch B. A person falling from a certain height receives more on a heap of sand injuries when he falls on a cemented floor than when he falls C. It is easier to push a lawn mower than to pull it D. Mountain roads are generally made winding upwards rather than going straight up

(A) Complete the following chemical equations : (i) Cu+HNO_(3) (dilute) to (ii) XeF_(4)+O_(2)F_(2)to (B) Explain the following observations: (i) Phosphorous has greater tendency for catenation than nitrogen. (ii) Oxygen is a gas but sulphur is a solid. (iii) The halogens are coloured. Why ?

(a) Draw the molecular structures of the following compounds : (i) N_(2)O_(5) " " (ii) XeOF_(4) (b) Explain the following observations : (i) Sulphur has a greater tendency for catenation than oxygen. (ii) ICI is more reactive than I_(2) . (iii) Despite lower value of its electron gain enthalpy with negative sign, fluorine (F_(2)) is a stronger oxidizing agent than Cl_(2) .

(a) Draw the structures of the following : (i) XeF_(4) (ii) H_(2)S_(2)O_(7) (iii) SO_(3)^(2-) (b) Explain the following observations : (i) Phosphorous has a greater tendency for catenation than nitrogen. (ii) The negative value of electron gain enthalpy is less for fluorine than that for chlorine. (iii) Hydrogen fluoride has a much higher boiling point than hydrogen chloride.