During nuclear explosion one of the products is ⁹⁰Sr with half-life of 28.1 yr. If 1 μg of ⁹⁰Sr was absorbed in the bones of a newly born body instead of calcium, how much of it will remain after 60 yr, if it is not lost metabolically?

• 0.184 μg

• 0.025 μg

• 0.262 μg

• 0.228 μg

A colloidal system having a solid substance as a dispersed phase and a liquid as a dispersion medium is classified as

• solid sol

• gel

• emulsion

• sol

In a first order reaction, the concentration of the reactant, decreases from 0.8 M to 0.4 M in 15 min. The time taken for the concentration to change from 0.1 M to 0.025 M is

• 30 min

• 15 min

• 7.5 min

• 160 min

Calculate the osmotic pressure of 0.01 M solution of cane sugar at 300 K (R = 0.08212 atm degree^-1 mol^-1)

• 0.3568 atm

• 0.2463 atm

• 0.1562 atm

• 0.5623 atm

Given, ${\mathrm{E}}_{{\mathrm{Cr}}^{3+}/ \mathrm{Cr}}^{°} = -0.72 \mathrm{V}, {\mathrm{E}}_{{\mathrm{Fe}}^{2+}/ \mathrm{Fe}}^{°} = -0.42 \mathrm{V}.$The potential for the cell Cr | Cr³⁺ (0.1 M) || Fe²⁺ (0.01 M) | Fe is

• 0.26 V

• 0.399 V

• -0.399 V

• -0.26 V

36.

In a reaction, A + B → C, the rate expression is R = k [A][B]². If the concentration of both the reactant is doubled at constant volume, then the rate of the reaction will be

• eight times

• double

• quadruple

• triple

Red lead is

• PbO

• Pb₃O₄

• PbO₂

• Pb₄O₃

Which among the following will anisotrophy?

• glass

• plastic

• barium chloride

• wood

Concentrated HNO₃ forms NO${}_2^{+}$ in the presence of

• Conc. H₂SO₄

• Fe

• FeBr₃

• AlCl₃

CH₃MgBr + CH₂ = CH-COH $\stackrel{{\mathrm{H}}_3{\mathrm{O}}^{+}}{\to }$ Product

It is (1 : 4 addition)

• CH₂=CH-$\underset{{\mathrm{CH}}_3}{\overset{\mathrm{OH}}{\underset{\left|}{\overset{\right|}{\mathrm{C}}}}}-\hspace{0.17em}\mathrm{H}$

• CH₂OH-CH=CH-CH₃

• CH₃CH₂CH₂CHO

• None of the above