Class 11th

We can write

$\stackrel{?}{\left|OM\right|}$ = $\left|\stackrel{?}{a}\right|\dots \dots \dots .\left(\mathrm{i}\right)$

$$ $\stackrel{?}{\left|MN\right|}$ = $\left|\stackrel{?}{b}\right|$ = $\stackrel{?}{\left|OP\right|}$ ………(ii)

$$ $\stackrel{?}{\left|ON\right|}$ = $\left|\stackrel{?}{a}+\stackrel{?}{b}\right|\dots \dots .\left(iii\right)$

In a triangle, each side is smaller than the sum of the other two sides. Therefore in ΔOMN, we have ON < (OM + MN)

$\left|\stackrel{?}{a}+\stackrel{?}{b}\right|$ < $\left|\stackrel{?}{a}\right|$ + $\left|\stackrel{?}{b}\right|$ ….(iv)

If the two vectors $\stackrel{?}{a}$ and $\stackrel{?}{b}$ act along a straight line in the same direction, then we can write $\left|\stackrel{?}{a}+\stackrel{?}{b}\right|$ = $\left|\stackrel{?}{a}\right|$ + $\left|\stackrel{?}{b}\right|\dots ..\left(v\right)$

Combining equations (iv) and (v), we get

$\left|\stackrel{?}{a}+\stackrel{?}{b}\right|$ $\le$ $\left|\stackrel{?}{a}\right|$ + $\left|\stackrel{?}{b}\right|$

8.45. What do you understand by Standard Electrode Potential? Explain.

8.44. What are the methods of balancing redox reactions.

8.43. Name the different types of redox reactions.

8.42. What is meant by electrochemical series? What are the characteristics of electrochemical series?

Questions and Answers:

8.41. Define electrochemical cell. How will you identify cathode and anode in an electrochemical cell?

8.39. Choose the incorrect statement.

(a) A redox couple consists of oxidised and reduced form of the same substance taking part in the oxidation or reduction half reaction.

(b) Oxidation involves gain of one or more electrons by a species during a reaction.

(c) Half reactions that involve loss of electrons are called oxidation reactions.

(d) Half reactions that involve gain of electrons are called reduction reactions.

8.38. Choose the incorrect statement.
(a) HNO₃ acts only as an oxidising agent while HNO₃ can act both as reducing and oxidising agent. 
(b) ClO₄^– does not show disproportionation reaction.
(c) Ozone acts as an oxidising agent.

(d) None of the above

MCQs

8.36. oxidation number ofS in S₂O₈^-2 is

(a) -2           (b) -6           (c) +2          (d) +6

5.42.  State and explain Dalton's law of partial pressures. Can we apply Dalton's law of partial pressures to a mixture of carbon monoxide and oxygen?