Neco Chemistry Past Questions and Answers

Question 76:

• NECO 2003

Which formula is used to indicate the degree of acidity of an acid?

A. \( [H^+] = ^{\text{mass of acid relative}} molecular mass of acid \)
B. F = number of H+ = ions x molar mass of the acid
C. Kw = [H+][OH-]
D. PH = - log₁₀[H+]
E. PKa = -log₁₀Ka

Question 77:

• NECO 2003

What is the IUPAC name of CH₃CCI=C(CH₃)2?

A. 2-chloro -3 methylbut -2yne
B. 2 -chloro -3 methylbut -2ene
C. 2 -chloro -3 methylbutene
D. 3- methyl -2-chlorobut -2-ene
E. 3- methyl -2. chlorobut -2 yne

Question 78:

• NECO 2003

What change will occur to the equilibrium mixture
\( 2CrO^{2-}_4(aq) + 2H^+(aq) ⇔ Cr_2O^{2-}_7(aq) + H_2O(l) \) when excess sodium hydrogen solution is added?

A. A yellow precipitate of Cr(OH)₃ is formed
B. An orange precipitate of Cr(OH)₃ is formed
C. The colour changes from orange to yellow
D. The colour changes from yellow to orange
E. There is no visible reaction.

Question 79:

• NECO 2003

Which element is the most electronegative?

A. Calcium
B. Fluorine
C. Iodine
D. Oxygen
E. Sodium

Question 80:

• NECO 2008

Which of the following compounds is unsaturated?

A. Cyclohexane
B. Methoxyethane
C. 1 ,2-dibromoethane
D. 2,2,3-trimethylpentane
E. 3-methylbut-l-ene