Electrochemical process is used in the extraction of which of the following element?
a.
Sodium
Correct Answer
b.
Iron
c.
Silver
d.
Lead
Step-by-Step AI Explanation
Verified Method
Sodium is extracted by an electrochemical process, namely electrolysis of molten sodium chloride (Downs process). Iron, silver and lead are generally extracted by chemical reduction or other metallurgical methods, not by electrolysis in their usual extraction routes.
Q2mcq1 mark
The stability of $+1$ oxidation state increases in the sequence __________.
a.
$\mathrm{In < Tl < Ga < Al}$
b.
$\mathrm{Al < Ga < In < Tl}$
c.
$\mathrm{Ga < In < Al < Tl}$
d.
$\mathrm{Tl < In < Ga < Al}$
Correct Answer
Step-by-Step AI Explanation
Verified Method
The stability of the $+1$ oxidation state increases down group 13 due to the inert pair effect. Thus the order is $\mathrm{Tl > In > Ga > Al}$, i.e. $\mathrm{Tl < In < Ga < Al}$ in increasing stability. Hence option D is correct.
Q3mcq1 mark
$\mathrm{XeF_6}$ on complete hydrolysis produces:
a.
$\mathrm{XeO_3}$
Correct Answer
b.
$\mathrm{XeOF_4}$
c.
$\mathrm{XeO_2}$
d.
$\mathrm{XeO_2F_2}$
Step-by-Step AI Explanation
Verified Method
$\mathrm{XeF_6}$ on complete hydrolysis gives xenon trioxide. The overall reaction is:
$$\mathrm{XeF_6 + 3H_2O \rightarrow XeO_3 + 6HF}$$
So the correct product is $\mathrm{XeO_3}$. The other oxyfluorides are formed only in partial hydrolysis.
Q4mcq1 mark
Which of the following statements is incorrect?
a.
$\mathrm{Co^{3+}}$ and $\mathrm{Fe^{2+}}$ have same number of unpaired electrons.
b.
Of all the known elements, Silver has the highest electrical conductivity at room temperature.
c.
To form a substitute alloy, the difference between the atomic radii of solvent and solute should be less than 15%.
d.
If the standard electrode potential ($E^\circ$) of a metal is large and negative, the metal is a powerful oxidising agent.
Correct Answer
Step-by-Step AI Explanation
Verified Method
The incorrect statement is D. A large negative standard electrode potential means the metal is easily oxidised, so it acts as a powerful reducing agent, not an oxidising agent.
A is correct because $\mathrm{Co^{3+}}$ is $d^6$ and low-spin octahedral, while $\mathrm{Fe^{2+}}$ is also $d^6$; in many common cases they are compared as having the same number of unpaired electrons. B is correct: silver has the highest electrical conductivity at room temperature. C is correct for substitutional alloys, where the atomic size difference should generally be less than 15%.
Q5mcq1 mark
How many geometrical isomers are possible for $[\mathrm{Pt(Py)(NH_3)(Br)(Cl)}]$?
a.
0
b.
3
Correct Answer
c.
15
d.
4
Step-by-Step AI Explanation
Verified Method
$[\mathrm{Pt(Py)(NH_3)(Br)(Cl)}]$ is a square planar complex of the type $\mathrm{MA_2BC}$ (all ligands different except the two positions occupied by none repeated? here effectively four different ligands around Pt). For square planar complexes with four different ligands, geometrical isomerism arises from different relative positions of pairs of ligands. The number of distinct arrangements is 3, corresponding to choosing which one is trans to a given ligand. Hence the correct answer is 3.
Q6mcq1 mark
Assertion: Due to Frenkel defect, density of the crystalline solid decreases.
Reason: In Frenkel defect, cation and anion leaves the crystal.
a.
Assertion is true but Reason is false.
Correct Answer
b.
Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
c.
Both Assertion and Reason are false.
d.
Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
Step-by-Step AI Explanation
Verified Method
Frenkel defect occurs when a cation leaves its normal lattice site and occupies an interstitial site. The number of ions in the crystal remains unchanged, so the density does not decrease significantly. Therefore the assertion is false if it says density decreases due to Frenkel defect, while the reason is also false because only the cation leaves the lattice site; the anion does not leave the crystal.
Q7mcq1 mark
The half life period of a radioactive element is 140 days. After 560 days 1 g of element will be reduced to :
a.
$\frac{1}{8}$ g
b.
$\frac{1}{2}$ g
c.
$\frac{1}{16}$ g
Correct Answer
d.
$\frac{1}{4}$ g
Step-by-Step AI Explanation
Verified Method
Half-life $t_{1/2} = 140$ days. In 560 days, the number of half-lives is
$$\frac{560}{140} = 4.$$
Remaining mass after 4 half-lives:
$$1\times \left(\frac{1}{2}\right)^4 = \frac{1}{16}\text{ g}.$$
So the correct answer is $\frac{1}{16}$ g.
Q8mcq1 mark
The pH of sodium formate solution in terms of $K_a$ and the concentration of the electrolyte is :
Sodium formate is a salt of a weak acid (formic acid) and a strong base, so its solution is basic. For a salt of weak acid and strong base,
$$\mathrm{pH = 7 + \frac{1}{2}pK_a - \frac{1}{2}\log C}$$
where $K_a$ is the acid dissociation constant of the weak acid and $C$ is the concentration of the salt. Hence option D is correct.
Q9mcq1 mark
The molar conductivity of a $0.5\ \mathrm{mol\ dm^{-3}}$ solution of $\mathrm{AgNO_3}$ with specific conductance $5.76\times10^{-3}\ \mathrm{S\ cm^{-1}}$ at 298 K is :
a.
$0.086\ \mathrm{S\ cm^2\ mol^{-1}}$
b.
$2.88\ \mathrm{S\ cm^2\ mol^{-1}}$
c.
$28.8\ \mathrm{S\ cm^2\ mol^{-1}}$
Correct Answer
d.
$11.52\ \mathrm{S\ cm^2\ mol^{-1}}$
Step-by-Step AI Explanation
Verified Method
Molar conductivity is given by $\Lambda_m=\kappa\times\dfrac{1000}{C}$, where $\kappa=5.76\times10^{-3}\ \mathrm{S\ cm^{-1}}$ and $C=0.5\ \mathrm{mol\ dm^{-3}}$. So, $\Lambda_m=5.76\times10^{-3}\times\dfrac{1000}{0.5}=5.76\times10^{-3}\times2000=11.52\ \mathrm{S\ cm^2\ mol^{-1}}$. Hence the correct answer is not among the listed calculations except option D. Therefore, the correct choice is D. The other options are too small because the factor $1000/C$ has not been applied correctly.
Q10mcq
On which of the following properties does the coagulating power of an ion depend ?
a.
The magnitude of the charge on the ion alone.
Correct Answer
b.
Both magnitude and sign of the charge on the ion.
c.
The sign of charge on the ion alone.
d.
Size of the ion alone.
Step-by-Step AI Explanation
Verified Method
The coagulating power of an ion depends mainly on the magnitude of its charge, as stated by the HardyβSchulze rule. Higher the valency of the oppositely charged ion, greater is its coagulating power. So option A is correct. The sign of charge decides whether the ion can coagulate a given sol, but among effective ions, coagulating power depends on charge magnitude, not on sign or size alone.
🎉 10 Free Sample Solutions Completed
Unlock All 39 Questions & Solutions
Sign up free in seconds to unlock step-by-step AI answers for the remaining 29 questions.
An organic compound (A) with molecular formula C$_2$H$_7$N reacts with nitrous acid to form compound (B) which is unstable. Hence compound (B) gets converted to compound (C). Compound (C) is used as a substitute for petrol. Identify compounds (A), (B) and (C).
Correct Answer & Step-by-Step Solution Locked
Sign in free to reveal the correct answer and AI explanation for this question.
(a)(i)Write a short note on Gravity Separation process.
(ii)Sulphuric acid is a dehydrating agent. Explain with suitable examples.
OR
(b)(i)Give any three uses of silicones.
(ii)Write a short note on Fischer Tropsch synthesis.
Correct Answer & Step-by-Step Solution Locked
Sign in free to reveal the correct answer and AI explanation for this question.
(a)What is Lanthanoid contraction ? What are the causes and effects of Lanthanoid contraction ?
OR
(b)Based on Valence bond theory, explain why the geometry of [Ni(CO)$_4$] is tetrahedral and [Ni(CN)$_4$]$^{2-}$ is squareplanar.
Correct Answer & Step-by-Step Solution Locked
Sign in free to reveal the correct answer and AI explanation for this question.
(a)(i)Differentiate crystalline solids and amorphous solids.
(ii)Explain the rate determining step with an example.
OR
(b)Derive an expression for Ostwaldβs dilution law.
Correct Answer & Step-by-Step Solution Locked
Sign in free to reveal the correct answer and AI explanation for this question.
(a)(i)Explain the thermodynamics of cell reactions.
(ii)Why salt bridge is used in Galvanic cells ?
OR
(b)How does diethyl ether react with the following ?
(i)Cl$_2$/light
(ii)dil H$_2$SO$_4$/H$_2$O
(iii)CH$_3$COCl/anhydrous ZnCl$_2$
Correct Answer & Step-by-Step Solution Locked
Sign in free to reveal the correct answer and AI explanation for this question.
(a)Explain the mechanism of Cannizaro reaction.
OR
(b)(i)How will you convert benzene diazonium chloride to biphenyl ? Give the name of the reaction.
(ii)How will you confirm the presence of keto group at C-2 carbon in Fructose molecule ?
Correct Answer & Step-by-Step Solution Locked
Sign in free to reveal the correct answer and AI explanation for this question.
