Δ U is equal to

• Isochoric work

• Isobaric work

• Adiabatic work

• Adiabatic work

The radius of the second Bohr orbit for the hydrogen atom is :
(Plank's const. h = 6.6262 × 10^–34 Js ; mass of electron = 9.1091 × 10–31 kg ; charge of electron
e = 1.60210 × 10^–19 C ; permittivity of vacuum
∈0 = 8.854185 × 10^–12 kg^–1 m^–3 A2)

• 1.65Å

• 4.76Å

• 0.529Å

• 0.529Å

p_Ka of a weak acid (H_A) and pKb of a weak base (BOH) are 3.2 and 3.4, respectively. The p_H of their salt (AB) solution is

• 7.2

• 6.9

• 7.0

• 7.0

The most abundant element by mass in the body of a healthy human adult are :
Oxygen (61.4%) ; Carbon (22.9%), Hydrogen(10.0%) ; and Nitrogen (2.6%). The weight which a 75 kg person would gain if all 1H atoms are replaced by 2H atoms is

• 15 kg

• 37.5 Kg

• 7.5 Kg

• 7.5 Kg

In the following reactions, ZnO is respectively acting as a/an :
(a) ZnO + Na₂O → Na₂ZnO₂
(b) ZnO + CO₂ → ZnCO₃

• base and acid

• base and base

• acid and acid

• acid and acid

6.

Given
C(grahite) + O₂(g) → CO₂(g)
Δ_rH°  = - 393.5 kJ mol^-1
H₂(g) + 1/2O₂(g) → H₂O (l)
Δ_rH°  = +890.3 kJ mol^-1
Based on the above thermochemical equations, the value of Δ_rH° at 298 K for the reaction
C(grahite) + 2H₂(g) →CH₄ will be

•  +74.8 kJ mol^–1 

• +144.0 kJ mol^–1

• –74.8 kJ mol^–1

• –74.8 kJ mol^–1

The group having isoelectronic species is

• O^2– , F^–, Na⁺ , Mg²⁺

• O– , F^–, Na, Mg⁺

• O^2–, F^–, Na ,Mg²⁺

• O^2–, F^–, Na ,Mg²⁺

Both lithium and magnesium display several similar properties due to the diagonal relationship; however, the one which is incorrect is :

• Both form basic carbonates

• Both form soluble bicarbonates

• Both form nitrides

• Both form nitrides

Which of the following molecules is least resonance stabilized?

A water sample has ppm level concentration of following anions

F^-= 10; SO₄^2- =100; NO₃^-= 50

the anion/anions that make/makes the water sample unsuitable for drinking is /are:

• only NO₃^-

• both 2 SO₄^- and NO₃^-

• only F^– 

• only F^–