Class 12th

Which amongst the following is not a pesticide?

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Class 12th Chemistry Coordination Compounds

Contributor-Level 9

DDT, organophosphates and dieldrin are pesticides.

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6 months ago

Given below are two statements:

Statement I : ${[N i {(C N)}_{4}]}^{2 -}$ is square planar and diamagnetic complex, with dsp² hybridizatin for Ni but $[N i {(C O)}_{4}]$ is tetrahedral, paramagnetic and with sp³ hybridization for Ni.

Statement II : ${[N i C l_{4}]}^{2 -} a n d [N i {(C O)}_{4}]$ both have same d-electron configuration have same geometry and are paramagnetic.

In light the above statements, choose the correct answer from the options given below:

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Contributor-Level 9

${[N i {(C N)}_{4}]}^{2 -}$

CN^- is strong field ligand

$N i^{2 +} = 4 s^{0} 3 d^{8}$

Here; ${[N i {(C N)}_{4}]}^{2 -}$ is square planar and diamagnetic.

$[N i {(C O)}_{4}]$

Ni = 4s²3d⁸ Co is strong field ligand.

Here ; $[N i {(C O)}_{4}]$ is tetrahedral and diamagnetic

${[N i {(C N)}_{4}]}^{2 -}$ has 3d⁸ configuration while $[N i {(C O)}_{4}]$ has 3d¹⁰ configuration.

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Class 12th Solutions

Elevation in boiling point for 1.5 molal solution of glucose in water is 4 K. The depression in freezing point for 4.5 molal solution of glucose in water is 4K. The ratio of molal elevation constant to molal depression constant (K_b/K_f) is________.

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Contributor-Level 10

$Δ T_{b} = i K_{b} m$

$Δ T_{f} = i K_{f} m$

$∴ \frac{4}{4} = \frac{K_{b} * 1.5}{K_{f} * 4.5}$

$\frac{K_{b}}{K_{f}} = 3$

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6 months ago

Which one of the lanthanoids given below is the most stable in divalent form?

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Contributor-Level 9

Valence shell electronic configuration of Eu in +2 O.S is,

$E u^{2 +} = 6 s^{0} 4 f^{7}$

It has half filled f-sub shell and stable.

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6 months ago

The mixture of chloroxylenol and terpineol is an example of

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Contributor-Level 10

Antiseptic Dettol is mixture of chloroxylenol and terpineol

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6 months ago

Given are two statements one is labeled as Assertion A and other is labeled as Reason R.

Assertion A : Magnesium can reduce Al₂O₃ at a temperature below 1350°C, while above 1350°C aluminium can reduce MgO

Reason R : The melting and boiling points of magnesium are lower thatn those of aluminium.

In light of the above statements, choose most appropriate answer for the options given below:

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Contributor-Level 9

Below 1350° C, Mg can reduce Al₂O₃ and above 1350°C, Al can reduce MgO (from Ellingham diagram).

Melting and boiling point of Mg are lower than that of Al.

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6 months ago

The structure of protein that is unaffected by heating is

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Contributor-Level 10

Primary structure of protein in unaffected by physical or chemical changes.

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6 months ago

The Zeta potential is related to which property of colloids?

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Contributor-Level 9

Potential difference between fixed layer and mobile layer of lyophobic colloid is called zeta potential or electro kinetic potential.

This potential difference is related to charge on the surface of colloidal particles.

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6 months ago

The incorrect statement about the imperfections in solids is:

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Contributor-Level 9

Density of solid decreases in Schottky defect and vacancy defect.
Density of solid increases in interstitial defect.
Density of solid remain unchanged in Frenkel defect.

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Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Dacron is an example of polyester polymer.

Reason R : Dacron is made up of ethylene glycol and terephthalic acid monomers.

In the light of the above statements, choose the most appropriate answer from the options given below.

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