Which choice(s) correctly rank(s) the bonds in terms of increasing polarity?

I. Cl?F < Br?Cl < Cl?Cl II. H?C < H?N < H?O

III. Br?F < I?F < Cl?F IV. Si?Cl < Si?P < Si?C < Si?F

I, II only
II only
II, IV only
I, III, IV only
I only

(II) only correctly rank the bonds in terms of increasing polarity.

Explanation:

Bond polarity is proportional to difference in electronegativity between bonded atoms.

Atoms    Electronegativity          Bond        Electronegativity difference

Cl                          3.0                       Cl-F                      1.0

Br                          2.8                       Br-Cl                     0.2

F                            4.0                       Cl-Cl                      0

H                            2.1                       H-C                       0.4

C                            2.5                       H-N                       0.9

N                             3.0                      H-O                       1.4

O                             3.5                      Br-F                       1.2

I                               2.7                      I-F                         1.3

Si                             1.9                      Cl-F                       1.0  

P                              2.2                      Si-Cl                      1.1

                                                          Si-P                        0.3

                                                          Si-C                        0.6

                                                           Si-F                        2.1

So, clearly, order of increasing polarity : O-H > N-H > C-H

So, (II) only correctly rank the bonds in terms of increasing polarity

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

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