Chemistry Past Questions and Answers

A white solid suspected to be lead trioxonitrate (V) zinc trioxocarbonate (IV) or calcium trioxocabonate (IV) was heated strongly. Its residue which was yellow when hot and white when cold is?

A Lead (II) oxide
B Calcium oxide
C Zinc oxide
D Lead nitrate

Question 472:

Which of the following compounds would give lilac flame coloration and a white precipitate with acidified barium chloride solution?

A KCI
B NaNO3
C K2SO4
D CaSO4

Question 473:

How will a metal X, which reacts explosively with air and with dilute acids be best extracted from its ores?

A Electrolysis of solution of its salts
B Decomposition of its oxides
C Displacement from solution by an alkali metal
D Electroiysis of fused salt

Question 474:

Which of the following is NOT correct test for the named organic compound in each case?

A Butanoic acid solution gives effervescence with Na2CO3 solution
B Glucose when reacted with Na2CrO4 at 0°C will show immediate discharge of colour
C When but-2-ene is reacted with dilute solution of KMnO4 the purple colour of KMnO is discharged readily even room temperature
D When butan-2-ol is boiled with butanoic acid with a drop of concentrated H2SO4 a sweet smelling liquid is produced

Question 475:

Which of the following is used as an 'anti-knock' in automobile engines?

A Tetramethyl silane
B Lead tetra-ethyl
C Glycerol
D N-heptane