How many neutrons are there in nucleus 'X', if it gives ₇N¹⁴ after two successive $\mathrm{\beta }$ - particle emissions ?

• 7

• 10

• 14

• 09

2.

2.0 molar solution is obtained, when 0.5 mole solute is dissolved in :

• 250 ml solvent

• 250 g solvent

• 250 ml solution

• 1000 ml solvent

The energy equivalent to 1 amu., is :

• 931.1 MeV

• 1.492 x 10¹³ erg

• 1000 J

• 10⁷ erg

Which particle can be used to change ₁₃Al²⁷ into ₁₅P³⁰ ?

• Neutron

• $\mathrm{\alpha }$ - particle

• Proton

• Deuteron

What will be the normality of a solution, containing 4.9 g. H₃PO₄ dissolved in 500 ml water ?

• 0.3

• 1.0

• 3.0

• 0.1

The solution obtained by adding water to alcohol, shows :

• +ve deviation from Raoult's law

• ideal behaviour

• -ve deviation from Raoult's law

• application of Henry's law

According to Bohr, the angular momentum of an electron, in any orbit, should be :

• h/2$\mathrm{\pi }$

• nh/2$\mathrm{\pi }$

• h/mv

• 2$\mathrm{\pi }$/nh

pH of a solution of 10 mL 1N sodium acetate and 50 mL 2N acetic acid (K_a = 1.8 x 10^-5), is approximately :

• 4

• 5

• 6

• 7

The pH is less than 7, of the solution of :

• FeCl₃

• NaCN

• NaOH

• NaCl

The values of K_sp for CuS, Ag₂S and HgS are 10^-31, 10⁴², 10^-54 respectively. The correct order of their solubility in water is :

• AgS > HgS > CuS

• HgS > Cus > Ag₂S

• HgS > Ag₂S > Cus

• Ag₂S > CuS > HgS