Analytical Chemistry — Chemistry STD 10 — Question

An element with atomic number 18 is a noble gas. Into which families will you place elements with atomic numbers 17 and 19 and why?

Define the following terms giving one example in each case (i) An acid (ii) A base (iii) An acid salt.

(a) (i) Name one most metallic element in the Periodic Table.
(ii) Name one most non-metallic element in the Periodic Table.
(b) How does electronegativity vary (i) in a period (ii) in a group?

Identify the following substances:
(i) An alkaline gas A which gives dense white fumes with hydrogen chloride.
(ii) A dilute acid B which does not normally give hydrogen when reacted with metals but does give a gas when it reacts with copper.
(iii) Gas C has an offensive smell like rotten eggs
(iv) Gas D is a colourless gas which can be used as a bleaching agent
(v) Liquid E can be dehydrated to produce ethene

Write a balanced equation for the following:
(i) C₂H₅Br + alcoholic KOH → ? (ii) CH₃CH₂COONa + soda lime? (iii) C₂H₄ + Br₂ → ?

How do metals differ from non-metals in :
(i) ion formation
(ii) electronic configuration
(iii) chemical nature of their oxides?

What are the conditions for the formation of an electrovalent bond?

Give three ways in which the metal zinc differs from the non-metals carbon. At least one of the differences must be a chemical difference ?

Using sodium hydroxide solution, how will you distinguish:
Lead hydroxide from magnesium hydroxide.

(i) Here is an electrode reaction:
Cu → Cu²⁺ + 2e^-
At which electrode (anode or cathode) would such a reaction take place? Is this an example of oxidation or reduction?
(ii) A solution contains magnesium ions (Mg²⁺), iron (II) ions (Fe²⁺) and copper ions (Cu²⁺). On passing an electric current through this solution, which ions will be the first to be discharged at the cathode? Write the equation for the cathode reaction.
(iii) Why is carbon tetrachloride, which is a liquid, a non-electrolyte?