If the electron configuration of a element is 1s² 2s²2P⁵, how many unpaired electron are there?

• A. 2
• B. 8
• C. 1
• D. 4

SO3 is not directly dissolved in water in the industrial preparation of HM2SO4 by the contact process because...

• A) SO3 is an acidic gas
• B) Acid is usually added to water and not water to acid
• C) The reaction between SO3 and water is violently exothermic
• D) SO3 does not dissolve readily in water does not dissolve readily in water

A decrease in atomic size and an increase in nuclear charge across a period lead to

• A. an increase in the tendency to lose electron
• B. an increase in chemical reactivity
• C. a decrease in electropositivity
• D. a decrease in covalency in bond formation

Calculate the mass of chlorine gas which occupies a volume of 1.12dm³ at s.t.p [Cl = 35.5, molar volume of gas at s.t.p = 22.4 dm³

• A. 15.50 g
• B. 7.10 g
• C. 3.55 g
• D. 1.80 g

Deliquescent substance are used for

• A. Cooling
• B. Wetting
• C. Melting
• D. Drying

The name of the compound CH₃C(CH₃)CH₂CH₂CH₃

• A. 2 - methyl butane
• B. 2,2 - dimethyl butane
• C. 2 - methyl pentane
• D. 2,2 - dimethyl pentane

If 0.20 moldm³ NaOH(aq) was evaporated to yield 5.0g of solid NaOH, calculate the volume of NaOH (aq) used. (Na = 23.0,O = 16:0; H = 1.00)

• A. 600cm³
• B. 625cm³
• C. 1000cm³
• D. 1600cm³

The carbon atoms on ethane are?

• A. sp2 hybridized
• B. sp3 hybridized
• C. sp2d hybridized
• D. sp hybridized

If gas A has a molar mass of 32 g/mol and gas B has a molar mass of 64 g/mol, what is the ratio of their diffusion rates?

• A. 2:1
• B. 1:2
• C. 1:1
• D. 1:4

Which of the following statements about nuclear reaction is correct? The reaction

• A. involves neutrons only
• B. takes place inside the nucleus
• C. is governed by temperature and pressure
• D. involves protons and electrons only