Trend in Electron Affinity

Q.

Which set of elements shows positive electron gain enthalpy?

1. $\mathrm{He},\mathrm{N},\mathrm{O}$

2. $\mathrm{Ne},\mathrm{N},\mathrm{CI}$

3. $\mathrm{O},\mathrm{CI},\mathrm{F}$

4. $\mathrm{N},\mathrm{He},\mathrm{Ne}$

Q.

Electron gain enthalpy of oxygen is less than that of sulphur. Why?

Q. Which of the following will not undergo Hell Volhard Zelinsky reaction ?

1. $C{H}_{3}COOH$
2. $C{H}_{3}C{H}_{2}COOH$
3. $2,2$-Dimethyl propionic acid
4. $2$-Methyl propionic acid

Q.

How would you account for the irregular variation of ionization enthalpies (first and second) in the first series of the transition elements?

Q.

Explain how vacancies are introduced in an ionic solid when a cation of higher valence is added as an impurity in it.

Q. Amongst the following which one will have maximum ‘lone pair-lone pair’ electron repulsions?

1. $S{F}_4$
2. $Xe{F}_2$
3. $I{F}_5$
4. $Cl{F}_3$

Q. Calculate the velocity of an electron placed in the second orbit of $L{i}^{2+}$ ion

1. $0.521m.s^{-1}$
2. $3.27\times {10}^{6}cm.s^{-1}$
3. $4.23\times {10}^{6}m.s^{-1}$
4. $3.27\times {10}^{6}m.s^{-1}$

Q. In the above reaction, Hofmann product is major when X is

1. -I
2. -Cl
3. -Br
4. -F

Q. Mole of thiosulphate ions required to react completely with one mole of permanganate ion in faintly alkaline medium is 1.2/5 2.2/3 3.3/8 4.3/

Q.

The second electron affinity is always endothermic no matter which element is under consideration. Justify.

Q. The Wurtz-Fittig reaction involves

1. two molecules of aryl halides
2. two molecules of alkyl halides
3. one molecule of each of aryl halide and alkyl halide
4. one molecule of each of aryl halide and phenol

Q.

why the third ionisation energy of manganese is unexpectedly high?

Q.

Why are all elements above $82$ are unstable?

Q.

Nitrogen has lower electron affinity than its preceeding element carbon because

1. Electron affinity decreases along a period.

2. Electron affinity generally increases along a period.

3. Nitrogen atom has half filled p-orbital

4. Nitrogen is a p-block element

Q. Considering the elements $F,Cl,OandS,$ the correct order of their electron affinity values is:

1. $F>Cl>O>S$
2. $F>O>Cl>S$
3. $Cl>F>S>O$
4. $O>F>S>Cl$

Q. Assertion: The electron gain enthalpy of $N$ is +ve while that of $P$ is -ve.

Reason: This is due to the smaller atomic size of N in which there is a considerable electron-electron repulsion and hence the additional electron is not accepted easily.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. In Finkelstein reaction, which reactant are used :

1. $NaI+C_2{H}_{5}OH$
2. NaF + acetone
3. $NaBr+C{H}_{3}OH$
4. $NaI+C{H}_{3}C{H}_{2}Br$

Q.

Match the corect ionisation enthalpies and electron gain enthalpies of the following elements.
$$\begin{array}{cccccc}& Elements& & △H_1& △H_2& {△}_{eg}H\\ \left(i\right)& Mostreactivenonmetal& A& 419& 3051& -48\\ \left(ii\right)& Mostreactivemetal& B& 1681& 3374& -328\\ \left(iii\right)& Leastreactiveelement& C& 738& 1451& -40\\ \left(iv\right)& Metalformingbinaryhalide& D.& 2372& 5251& +48\end{array}$$

Q. Which one of the following arrangements represents the correct order of least negative to most negative electron gain enthalpy for $C,Ca,Al,F\text{and}O$?

1. $Ca<Al<C<O<F$
2. $Al<Ca<O<C<F$
3. $Al<O<C<Ca<F$
4. $C<F<O<Al<Ca$

Q.

Define the drift velocity of free electrons.

Q. The number of moles $HI{O}_4$ required in the given reaction is:

Q. Choose the correct option(s).

1. Oxygen has the highest electron gain enthalpy among the chalcogens.
2. $B{e}^{+2}<L{i}^{+}<N{a}^{+}<K^{+}\text{radii}$.
3. $F$ is the 2nd most electronegative element.
4. $Cl$ has the highest negative electron gain enthalpy.

Q. Wurtz reaction is used to prepare:

1. Alkyl halides
2. Symmetrical alkanes
3. Unsymmetrical alkanes
4. All of these

Q.

Find the number of Na⁺ &PO^-3_{​​​​4} ions kind 250 ml of 0.2 M Na3PO4 solution.

Q. The electron affinity of fluorine is less than that of chlorine because:

1. the electron density in fluorine is higher.
2. fluorine has lower ionisation potential than chlorine.
3. the incoming electron enters the 2p orbitals in fluorine and 3p orbital in chlorine.
4. the incoming electron enters the 3p orbital in fluorine.

Q.

Which of the following elements does not lose an electron easily?

1. $\mathrm{Na}$

2. $\mathrm{F}$

3. $\mathrm{Mg}$

4. $\mathrm{Al}$

Q.

Which among the following pairs of elements have maximum and minimum electron affinity values respectively?

1. Be, Cl

2. He, K

3. Be, S

4. Cl, Cs

Q. What is the ratio of time periods $\left(T_1/T_2\right)$ in second orbit of hydrogen atom to third orbit of $H{e}^{+}$ ion?

1. $\frac{8}{27}$
2. $\frac{32}{27}$
3. $\frac{27}{32}$
4. $\frac{16}{27}$

Q. Why do other elements of group 15 except nitrogen can exhibit covalency of six , not five ??

Q.

Which of the following has highest electron affinity?

1. Cl

2. F

3. N

4. O