1411. The ancient greeks said that the four elements were Earth, Air, Water and Fire. in 390 BC, plato added a fifth element to this list . What was it ?

A. Ether *
B. Blood
C. Carbon
D. Nitrogen

1412. Which substance was the first organic chemical to be synthesized from an inorganic source ?

A. Urea *
B. Hellinic acid
C. Hydrochloric acid
D. Aqua regia

1413. In 1898, Pierre and Marie curie separated two radioactive elements . What were they ?

A. Radium and polonium *
B. Radium and Thorium
C. Polonium and Thorium
D. Polonium and Uranium

1414. The element which form Amphoteric oxides is :

A. Antimony *
B. Bismuth
C. Sodium
D. Phosphorous

1415. The single acid which dissolves gold is ?

A. Nitric acid
B. Selenic acid
C. Hydrochloric acid
D. Aqua regia *

1416. Which of these one substances contains no oxygen ?

A. Cryolite *
B. Bauxite
C. Dolomite
D. Epsom salt

1417. Which gas is used for converting vegetables oils into saturated fats ?

A. H2 *
B. O2
C. CL2
d. SO2

1418. Which one of the following is used in the preparation of antiseptic solution ?

A. Iodine *
B. Iodine chloride
C. Potassium Chloride
D. Potassium Nitrate

1419. Which one of the following is the softest ?

A. Iron
B. Lithium
C. Silicon
D. Sodium *

1420. A balloon filled with helium rises in air because____:

A. The air below the balloon is pressed down on by helium.
B. The balloon is weightless
C. Air exerts an upward force on the balloon
D. Helium is less dense than air *