Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Chlorine is an electron withdrawing group but it is ortho, para directing in electrophilic aromatic substitution.
Reason (R) : Inductive effect of chlorine destabilises the intermediate carbocation formed during the electrophilic substitution, however due to the more pronounced resonance effect, the halogen stabilises the carbocation at ortho and para positioins.
In the light of the above statements, choose the most appropriate answer from the options given below :
Two half cell reactions are given below.
$$C{o^{3 + }} + {e^ - } \to C{o^{2 + }},\,\,\,\,\,\,\,\,\,E_{C{o^{2 + }}/C{o^{3 + }}}^0 = - 1.81\,V$$
$$2A{l^{3 + }} + 6{e^ - } \to 2Al(s),\,\,\,E_{Al/A{l^{3 + }}}^0 = + 1.66\,V$$
The standard EMF of a cell with feasible redox reaction will be :
Match List-I with List-II :
List-I (Compounds) |
List-II (Molecular formula) |
||
---|---|---|---|
(a) | Borax | (i) | NaBO$$_2$$ |
(b) | Kernite | (ii) | Na$$_2$$B$$_4$$O$$_7$$ . 4H$$_2$$O |
(c) | Orthoboric acid | (iii) | H$$_3$$BO$$_3$$ |
(d) | Borax bead | (iv) | Na$$_2$$B$$_4$$O$$_7$$ . 10H$$_2$$O |
Choose the correct answer from the options given below :
The correct order of first ionization enthalpy for the given four elements is :