A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 37.0⁰C. As it does so, it absorbs 208J of heat. The values of q and w for the process will be:(R = 8.314 J/mol K) ( ln 7.5 = 2.01)

• q =+208J, W = - 208 J

• q =-208 J, W =-208 J

• q=-208J, W = +208 J

• q=-208J, W = +208 J

For the gaseous state, if most probable speed is denoted by C*, average speed by C and mean square speed by C, then for a large number of molecules the ratios of these speeds are:

A gaseous hydrocarbon gives upon combustion 0.72 g of water and 3.08 g of CO₂.The empirical formula of the hydrocarbon is 

• C₂H₄

• C₃H₄

• C₆H₅

• C₆H₅

In which of the following pairs of molecules/ions, both the species are not likely exist?

5.

Which of the following exists as covalent crystals in the solid state?

• Iodine

• Silicon

• Sulphur

• Sulphur

Which of the following represents the correct order of increasing first ionisation enthalpy for Ca, Ba, S, Se and Ar?

• Ca <S<Ba<Se<Ar

• S< Se<Ca<Ba< Ar

• Ba< Ca<Se< S< Ar

• Ba< Ca<Se< S< Ar

Energy of an electron is given by
E =- 2.178 x 10^-18 J 
Wavelength of light required to excite an electron in a hydrogen atom from level n =1 to n=2 will be (h=6.62 x 10³⁴ Js and c = 3.0 x 10⁸ ms^-1) 

• 1.214 x 10^-7 m

• 2.816 x 10^-7 m

• 6.500 x 10^-7 m

• 6.500 x 10^-7 m

The first ionisation potential of Na is 5.1 eV. The value of electron gain enthalpy of Na⁺ will be

• -2.55 eV

• -5.1 eV

• -10.2 eV

• -10.2 eV

Stability of the species Li₂, Li₂⁻ and Li₂⁺ increases in the order of:

• Li₂ < Li₂⁺ < Li₂^-

• Li₂⁻ < Li₂⁺ < Li₂ 

• Li₂< Li₂⁻ < Li₂⁺

• Li₂< Li₂⁻ < Li₂⁺

Experimentally it was found that a metal oxide has formula M_0.98O. Metal M, is present as M²⁺ and M³⁺ in its oxide. The fraction of the metal which exists as M³⁺ would be:

• 7.01%

• 4.08%

• 6.05%

• 6.05%