Chemistry

The following are s-block elements except?

A. lithium B. magnesium C. potassium D. calcium E. aluminium Correct Answer: Option E - aluminium

5 years ago

Given that for the reaction. N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H = -92kJ. What is the enthalpy of formation of ammonia from its elements?

A. -46KJ mol -1 B. -184KJmol -1 C. -92KJmol -1 D. 184KJmol -1 E. +46KJmol -1 Correct Answer: Option A…

5 years ago

If sulphur is dissolved in carbon (IV) sulphide and the solution is allowed to evaporate, the allotrope of sulphur formed is?

A. plastic sulphur B. amorphous sulphur C. rhombic sulphur D. monoclinic sulphur E. colloidal sulphur Correct Answer: Option C -…

5 years ago

Which of the following is used extensively in manufacturing photographic chemicals?

A. Aluminium chloride B. Zinc chloride C. Silver chloride D. Mercury (ll) chloride E. lron (ll) chloride Correct Answer: Option…

5 years ago

Octane number is highest in petrol containing a high proportion of?

A. heptane B. octane C. 2-methylpentane D. 2, 4-dimethylpentane E. 2,2,4-trimethylpentane Correct Answer: Option E - 2,2,4-trimethylpentane

5 years ago

The rate of the hydrogen in the reaction Zn(s) + 2HCI (aq) → ZnCI2(aq) + H2(g) can be increased by?

A. using Zinc powder instead of Zinc granules B. using dilute instead of concentrated hydrochloric acid C. cooling the container…

5 years ago

Why is potassium fluoride added to the electrolyte in the extraction of sodium from fused sodium chloride?

A. Pure sodium chloride does not conduct electricity B. Potassium fluoride prevents the sodium produced from attacking the electrodes C.…

5 years ago

Locally produced soap in which wood ash is used as the base is usually soft because the wood ash contains a lot of?

A. sodium ions B. potassium ions C. lithium ions D. calcium ions E. magnesium ions Correct Answer: Option B -…

5 years ago

Copper can best be purified by?

A. roasting the impure copper in a blast furnace B. heating the oxide with coke C. electrolyzing a copper (ll)…

5 years ago

Which of the following carbohydrates does NOT usually occur in the crystalline form?

A. Fructose B. Glucose C. Sucrose D. Maltose E. Cellulose Correct Answer: Option E - Cellulose

5 years ago