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Multiple choice chemistry chemical bond and chemical equation coordinate bond types of bonds and properties chemical bonding and structure

Consider following compounds:


$I: K _4[Fe(CN) _6], II:NH _4Cl, III: H _2SO _4$ 

Ionic, covalent and coordinate bonds are present in :

  1. I, II and III

  2. I and III

  3. II and III

  4. I and II
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$H _{2}SO _{4}$  has $3$ types of bonds- ionic, covalent and coordinate. Sulphur is the central atom,surrounded by $4$ oxygen atoms and $2$ hydrogen atoms places on left of any $2$ oxygen atoms. Now, oxygen shares one electron each with the sulphur and hydrogen atom. But by this only $2$ oxygen atoms will be able to complete octet. The remaining $2$ will complete by coordinate bonding. Both the oxygen atoms will take electrons from sulphur but sulphur won't take theirs ie sharing from only one end. This is called coordinate bond. Hydronium ions are attached with sulphate ions using ionic bonding
${ K } _{ 4 }[{ Fe(CN) } _{ 6 }]\ $: has ionic bond between ${ K }^{ + }and  { [{ Fe(CN) } _{ 6 }] }^{ 4- }$, coordinate bonding in $CN$ and covalent bond in ${ [{ Fe(CN) } _{ 6 }] }^{ 4- }$
$\ { NH } _{ 4 }Cl\ $: has ionic bond between $\ { { NH } _{ 4 } }^{ + }and  { Cl }^{ -}$, coordinate bonding in $\ { { NH } _{ 4 } }^{ + }$ and covalent bond in $\ { { NH } _{ 3 } .}^{  }\quad \$

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Which of the following contains a coordinate covalent bond ?

  1. $N _2H^{+} _{5}$
  2. $BaCl _2$
  3. $HCl$
  4. $H _2O$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

${ N } _{ 2 }{ H } _{ 5 }^{ + }$ is formed from ${ N } _{ 2 }{ H } _{ 4 }$ which has a lone pair of electrons on $'N'$ and positive charge on $'H'$ takes away its electron and to complete duplet, a co-ordinate bond is present from $N$ to $H$.

$H _4N _2 + H^+ \rightarrow[H _4N _2\to H]^+$

Multiple choice chemistry chemical bonding and structure coordinate bond types of bonds and properties chemical bond and chemical equation

Which of the following molecule has dative bond?

  1. CO
  2. $CO _3^{2-}$
  3. $SO _4^{-2}$

  4. All of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Carbon monoxide (CO) contains a dative (coordinate) bond where oxygen donates a lone pair to carbon to complete its octet. While other options also involve coordinate bonding in their Lewis structures, CO is the most classic example of a simple molecule defined by this feature.

Multiple choice chemistry chemical kinetics kinetic study of some first order reactions rate of chemical reaction endothermic and exothermic reactions

The first order rate constant for dissociation of $N _2O _5$ is $6.2\times 10^{-4}s^{-1}$. The half-life period (in $s$) of this dissociation will be.

  1. $1117.7$
  2. $111.7$
  3. $223.4$
  4. $160.9$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
$t _{1/2}=\displaystyle\frac{0.693}{k}$
$=\displaystyle\frac{0.693}{6.2\times 10^{-4}}=1117.7s$
Multiple choice chemistry chemical kinetics kinetic study of some first order reactions rate of chemical reaction endothermic and exothermic reactions

How many minutes will it take to plate out $5.0g$ of $Cr$ form a $Cr _2(SO _4) _3$ solution using a current of $1.50A$?

  1. $254$
  2. $309$
  3. $152$
  4. $103$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Using Faraday's law, mass = (I * t * M) / (n * F). For Cr2(SO4)3, Cr is in the +3 oxidation state (n=3). Molar mass of Cr is 52g/mol. t = (5.0 * 3 * 96500) / (1.5 * 52) = 18557 seconds. 18557 / 60 = 309 minutes.

Multiple choice chemistry chemical kinetics kinetic study of some first order reactions rate of chemical reaction endothermic and exothermic reactions

Which of the following is first order ?
i) Decomposition of $NH _{4}NO _{3}$ in aqueous solution.
ii) Inversion of cane sugar in the presence of an acid
iii) Base hydrolysis of ethyl acetate.
iv) All radioactive decays.
The correct combination is:

  1. i, ii, iv

  2. All are correct

  3. ii, iv

  4. ii, iii, iv
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Base hydrolysis of ethyl acetate is a second order reaction.
The other reactions are first order reactions.

Multiple choice chemistry chemical kinetics kinetic study of some first order reactions rate of chemical reaction endothermic and exothermic reactions

The acid hydrolysis of the ester is:
(i) first order reaction
(ii) bimolecular reaction
(iii) unimolecular reaction
(iv) second order reaction

The true statements are:

  1. i, ii

  2. All are correct

  3. ii, iv

  4. ii, iii, iv
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$CH _{3}COOC _{2}H _{5}+H _{2}O\rightarrow CH _{3}COOH+C _{2}H _{5}OH$
$ rate=K[CH _{3}COO\ C _{2}H _{5}]^{1}[H _{2}O]^{0}$
thus, it is first order & bi molecular reaction.

Thus, statement i and ii are correct.

Multiple choice chemistry chemical kinetics kinetic study of some first order reactions rate of chemical reaction endothermic and exothermic reactions

The hydrolysis of acetic anhydride$(CH _3CO) _2O+ H _2O\rightarrow2CH _3COOH$ is an example of :

  1. Pseudo first order reaction

  2. Pseudo second order reaction

  3. Zero order reaction

  4. Third order reaction
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is an example of pseudo first order reaction because here $H _{2}O$ is in excess. Thus, rate of reaction depends on only concentration of acetic anhydride.
So, rate is given by
$=k[(CH _{3}CO) _{2}O]$