The value of entropy of solar system is

• Increasing

• decreasing

• constant

• zero

The number of water molecules present in a drop of water weighing 0.018 g is

• 6.022 × 10²⁶

• 6.022 × 10²³

• 6.022 × 10¹⁹

• 6.022 × 10²⁰

Empirical formula of a compound is CH₂O and its molecular mass is 90, the molecular formula of the compound is

• C₃H₆O₃

• C₂H₄O₂

• C₆H₁₂O₆

• CH₂O

4.

Hybridised states of carbon in graphite and diamond are respectively

• sp³, sp³

• sp³, sp²

• sp², sp²

• sp² , sp³

The mass of 112cm³ of NH₃ gas at STP is

• 0.085g

• 0.850g

• 8.500g

• 80.500g

The yield of the products in the reaction A₂(g) + 2B(g) $\rightleftharpoons$C(g) + kJ would be higher at

• high temperature and high pressure

• high temperature and low pressure

• low temperature and high pressure

• low temperature and low pressure

Which of the following gases has the highest value of RMS velocity at 298 K?

• CH₄

• CO

• Cl₂

• CO₂

Given thermochemical equation, 2H₂ (g) + O₂(g) → 2H₂O,ΔH = -571.6 kJ. Heat of decomposition of water is

• -571.6 kJ

• +571.6 kJ

• -1143.2 kJ

• + 285.8 kJ

An example for a neutral buffer is

• ammonium hydroxide and ammonium chloride

• acetic acid and sodium acetate

• acetic acid and ammonium hydroxide

• citric acid and sodium citrate

Conjugate base of H₂PO${}_4^{2-}$

• H₃PO${}_4^{-}$

• HPO${}_4^{2-}$

• H₃PO₄

• PO${}_4^{3-}$