Chemistry

Assuming 1 $\mu g$  of trace radioactive element X with a half life of 30 years is absorbed by a growing tree. The amount of X remaining in the tree after 100 years is __________* 10^-1   $\mu g$

[Given: In 10 = 2.303; log 2 = 0.30]

 1.80g of solute A was dissolved in 62.5cm³ of ethanol and freezing point of the solution was found to be 155.1 K . The molar mass of solute A is __________g mol^-1.

[Given: Freezing point of ethanol is 156.0 K. Density of ethanol is 0.80 g cm^-3. Freezing point depression constant of ethanol is 2.00 K kg mol^-1]

Consider, PF₅, BrF₅, PCl₃, SF₆, ${\left[IC{l}_4\right]}^{-}$ , CIF₃ and IF₅.

Amongst the above molecule(s) / ion(s), the number of molecule(s) / ion(s) having sp³d² hybridisation is_____________.

'x' g of molecular oxygen(O₂) is mixed with 200g of neon (Ne). The total pressure of the non-reactive mixture of O₂ and Ne in the cylinder is 25 bar. The partial pressure of Ne is 20 bar at the same temperature and volume. The value of 'x' is_________.

If O₂ gas is bubbled  through water at 303 K, the number of millimoles of O₂ gas that dissolve in 1 litre of water is______________. (Nearest integer)

(Given: Henry’s Law constant for O₂ at 303 K is 46.82 k bar and partial pressure of O₂ = 0.920 bar)

(Assume solubility of O₂ in water in too small, nearly negligible)

When 600 mL of 0.2 M HNO₃ is mixed with 400 mL of 0.1 M NaOH solution in a flask, the rise in temperature of the flask is_________ * 10^-2 °C.

(Enthalpy of neutralization = 57 kJ mol^-1 and Specific heat of water = 4.2 JK^-1 g^-1)

(Neglect heat capacity of flask)

The minimum uncertainty in the speed of an electron in an one dimensional region of length 2a₀ (Where a₀ = Bohr radius 52.9 pm) is__________ km s^-1.

(Given: Mass of electron = 9.1 * 10^-31 kg, Planck's constant h = 6.63 * 10^-34 Js)

Ionic radii of cation A⁺ and anion B^- are 102 and 181 pm respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for B^-. A⁺ is present in all octahedral voids. The edge length of the unit cell of the crystal AB is________ pm.

(Nearest integer)

Resistance of a conductivity cell (cell constant 129 m^-1) filled with 74.5 ppm solution of KCl is $100\Omega$  (labeled as solution 1). When the same cell is filled with KCl solution of 149 ppm, the resistance is $50\Omega$  (labeled as solution 2). The ratio of molar conductivity of solution 1 and solution 2 is i.e. $\frac{{\wedge }_1}{{\wedge }_2}=x*10^{-3}.$  The value of x is________. (Nearest integer)

On complete combustion of 0.492g of an organic compound containing C, H and O, 0.7938 g of CO₂ and 0.4428 g of H₂O was produced. The % composition of oxygen in the compounds is____________.