Chemistry Quiz

the gas which burns with a pop sound

• hydrogen
• oxygen

• nitrogen

• carbon dioxide

the valency of chlorine in the compound MgCl₂

• − 1

• − 2

• 0

• • + 1

Answer explanation

think of criss-cross
Cl has 2 which has come from magnesium valency 2
Mg has 1 (no number there means 1) which comes from chlorine valency 1

metals have positive valency
non metals have negative valency

the valency of sodium in the compound NaCl

• − 1

• + 1

• − 2

• 0

the gas that is essential for respiration

• carbon dioxide

• oxygen

• nitrogen

• hydrogen

the element that has the atomic number 6

• oxygen

• carbon

• nitrogen

• helium

the element that is a noble gas

• argon

• hydrogen

• chlorine

• oxygen

a base from the following compounds

• NaCl
• KCl
• HCl
• NaOH

an acid from the following compounds

• H₃PO₄

• C₆H₁₂O₆

• H₂O

• NaOH

the element that is a halogen

• bromine

• helium

• argon

• krypton

the catalyst used in the preparation of ammonia

• Iron
• Copper
• Nickel
• Zinc