117) Which of the following is a synthetic indicator?

A) Turmeric
B) Methyl orange
C) Litmus solution
D) Red cabbage extract

118) Why do acidic solutions conduct electricity?

A) Due to the presence of water molecules
B) Due to the presence of free electrons
C) Due to the presence of ions in the solution
D) Because acids are solid conductors

119) Tooth decay begins when the pH of the mouth drops below:

A) 6.5
B) 5.5
C) 4.5
D) 7.0

120) What chemical is responsible for the pain caused by a bee sting?

A) Methanoic acid
B) Hydrochloric acid
C) Acetic acid
D) Sulphuric acid

121) What is the chemical formula of Plaster of Paris?

A) CaSO₄ ·2H₂O
B) CaSO₄ ·½ 2H₂O
C) CaCO₃
D) CaOCl₂

122) Which property of metals describes their shiny surface?

A) Malleability
B) Ductility
C) Metallic luster
D) Conductivity