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Class 12th Chemistry

3.12g of oxygen is adsorbed on 1.2g of platinum metal. The volume oxygen adsorbed per gram of the adsorbent at 1 atm and 300 K in L is-----------.

[R = 0.0821 L atm K^-1 mole^-1]

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Payal Gupta

Contributor-Level 10

PV = nRT

1 * V = $\frac{3.12}{32} * 0.0821 * 300$

V = 2.4 litre

Vol of O₂ adsorbed per gm = 2.4 / 1.2 = 2 litre

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Class 12th Chemistry

Dichromate ion is treated with base, the oxidation number of Cr in the product formed is-----------.

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Payal Gupta

Contributor-Level 10

$C r_{2} O_{7}^{2 -} + 2 O H^{-} \to 2 C r O_{4}^{2 -} + H_{2} O$

Dichromate ion converted to chromate ion in basic medium and oxidation number of Cr in $C r O_{4}^{2 -}$ is +6.

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Class 12th Chemistry Chemical Kinetics

An exothermic reaction X → Y has an activation energy 30 kJ mol^-1. If energy change $Δ E$ during the reaction is -20 kJ, then the activation energy for the reverse reaction in kJ is-----------. (Integer answer)

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Payal Gupta

Contributor-Level 10

X → Y

$\begin{array}{l} E_{a_{f}} - E_{a_{b}} = - 20 \\ 30 - E_{a_{b}} = - 20 \end{array}$

$E_{a_{b}} = 50 k J / m o l e$

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10 months ago

Class 12th Chemistry Electrochemistry

Consider the following reaction

$M n O_{4}^{-} + 8 H^{+} + 5 e^{-} \to M n^{+ 2} + 4 H_{2} O, E ° = 1.51 V .$

The quantity of electricity required is Faraday to reduce five moles of $M n O_{4}^{-}$ is--------.

(Integer answer)

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Payal Gupta

Contributor-Level 10

$M n O_{4}^{-} + 8 H + 5 e^{-} \to M n + 4 H_{2} O E^{o} = 1.51 V$

Quantity of electricity required to reduce 1 mole of $M n O_{4}^{-}$ is 5F

So, for 5 mole $M n O_{4}^{-}$ 25F electricity is required.

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Class 12th Chemistry

Number of bridging CO ligands in $[M n^{2} {(C O)}_{10}]$ is----------.

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Payal Gupta

Contributor-Level 10

[Mn₂ (CO)₁₀]

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Class 12th Chemistry

For the given reaction

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Payal Gupta

Contributor-Level 10

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Class 12th Chemistry

The presence of ozone is troposphere

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Payal Gupta

Contributor-Level 10

O₃ generally exist in stratosphere and they acts as protector, because it protect us from harmful UV radiations but sometimes O₃ formed in troposphere and it acts as a pollutants.

O₃ in stratosphere : - Protector

O₃ in Troposphere : - Pollutant (photochemical smog)

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Class 12th Chemistry

Given below are two statements:

Statements I : o- Nitrophenol is steam volatile due to intramolecular hydrogen bonding.

Statement II : o- Nitrophenol has high melting due to hydrogen bonding.

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

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