Chemistry (Part-IV)

1. Metals have _______ . [S.S.C. Online MTS (T-I) 4.10.2017]

(a) High melting and boiling point
(b) Low melting and boiling point
(c) High melting and low boiling point
(d) Low melting and high boiling point

Correct Answer: (a) High melting and boiling point

Solution:Metals generally have a high melting point and high boiling point. This is due to the strong attraction between metallic bonds, because these positive metallic ions are very tightly bound between large amounts of free electrons.

2. Metals are generally _______ . [S.S.C. Online CHSL (T-I) 7.03.2018 ]

I. Ductile

II. Malleable

III. Poor conductors of heat

(a) Only I and II
(b) Only I and III
(c) Only II and III
(d) All I, II and III

Correct Answer: (a) Only I and II

Solution:Metal are generally ductile, malleable and good conductor of heat and electricity. Ductility is a property where a substance can be drawn into thin wires. Metals are malleable because they consist of layers of atoms. These layers can slide over one another when the metal is bent, hammered or pressed.

3. Which of the following metals is the most ductile? [S.S.C. Online Constable GD 12.02.2019]

(a) Aluminium
(b) Iron
(c) Gold
(d) Copper

Correct Answer: (c) Gold

Solution:Generally, malleability (soft) and ductile properties are found in all metals, and gold (Au) is the most ductile among the given metals. Mercury (Hg), sodium (Na), and potassium (K) do not possess the malleable and ductile properties of metals, these being exceptions.

4. Which of the following metals is the most ductile metal? [S.S.C. Online Graduate Level (T-I) 6.06.2019]

(a) Copper
(b) Aluminium
(c) Gold
(d) Tin

Correct Answer: (c) Gold

5. What is the symbol of gold? [S.S.C. Online MTS (T-I) 6.08.2019]

(a) Mg
(b) Hg
(c) Ag
(d) Au

Correct Answer: (d) Au

Solution:The symbol of gold is Au, derived from the Latin word "aurum."

6. What is the molecular formula of gold? [S.S.C Online Constable GD 12.02.2019]

(a) Al
(b) G
(c) Au
(d) Ag

Correct Answer: (c) Au

Solution:The molecular formula of gold is Au. Gold exists as individual atoms in its elemental form, so its formula is simply its symbol.

7. Metallurgy is the process of _______ . [S.S.C. Online MTS (T-I) 4.10.2017]

(a) Extracting metals from Ore
(b) Roasting Ore
(c) Liquefaction of metals
(d) Adding metal to Ore in blast furnace

Correct Answer: (a) Extracting metals from Ore

Solution:
Extracting metals from Ore is the process of metallurgy. It involves various physical and chemical methods to obtain pure metals from their naturally occurring ores.

8. Metals generally form _______ . [S.S.C. Online MTS (T-I) 5.10.2017]

(a) Basic oxides
(b) Acidic oxides
(c) Neutral oxides
(d) Both basic and neidic oxides

Correct Answer: (a) Basic oxides

Solution:Metals generally form Basic oxides. Metal oxides react with acids to form salts and water. Some metals can also form amphoteric oxides, which exhibit both acidic and basic properties.

9. Which of the following liquids can dissolve noble metals such as gold and platinum? [S.S.C. Online CPO SI (T-I) 10.11.2022]

(a) Formic acid
(b) Aqua regia
(c) Acetic acid
(d) Chloroform

Correct Answer: (b) Aqua regia

Solution:
Aqua regia is a highly corrosive mixture of nitric acid and hydrochloric acid, optimally in a molar ratio of 1:3. It is one of the few reagents that can dissolve noble metals like gold and platinum.

10. Which of the following is not a donor atom? [S.S.C. Online Graduate Level (T-I) 3.09.2016]

(a) Phosphorus
(b)timony
(c) Arsenic
(d) Aluminium

Correct Answer: (d) Aluminium

Solution:

A donor atom in the context of semiconductors typically refers to an impurity atom with more valence electrons than the semiconductor atom it replaces (e.g., Silicon or Germanium). These extra electrons are donated to the conduction band.

Phosphorus (P) has 5 valence electrons and can be a donor in Silicon (4 valence electrons).
Antimony (Sb) has 5 valence electrons and can be a donor in Silicon.
Arsenic (As) has 5 valence electrons and can be a donor in Silicon.
Aluminium (Al) has 3 valence electrons and would act as an acceptor atom (creating holes) in Silicon.

Therefore, Aluminium is not a donor atom in the context of n-type semiconductor doping of Silicon or Germanium.