Chemistry Section 1 - General Knowledge Questions and Answers

Chemistry - Section 1

36.

The ionic radii of N^3-, O^2-, F^- and Na⁺ follows the order

A.	N^3- > O^2- > F^- > Na⁺
B.	एन ³ > Na ⁺ > हे ^2- > एफ ^-
C.	Na ⁺ > हे ^2- > एन ³ > एफ ^-
D.	हे ^2- > एफ ^- > Na ⁺ > एन ³

37.

The first metal used by man was

A.	iron
B.	तांबा
C.	सोना
D.	पीतल

38.

The hydronium ion is

A.	H⁺
B.	हो -
C.	एच 2 ⁺
D.	एच ₃ हे ⁺

39.

The method that cannot be used for removing permanent hardness of water is

A.	adding sodium carbonate
B.	आसवन
C.	कास्टिक सोडा जोड़ने
D.	उबलना

40.

The following are the half lives of four active isotopes. Which one of the following is the most dangerous to handle?

A.	3 billion years
B.	100 वर्ष
C.	0.01 मिनट
D.	13 दिन