मराठी
कर्नाटक बोर्ड पी.यू.सी.पीयूसी विज्ञान 2nd PUC Class 12

Assertion: CuX2+ iodide is not known. Reason: CuX2+ oxidises IX− to iodine.

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प्रश्न

Assertion: \[\ce{Cu^2+}\] iodide is not known.

Reason: \[\ce{Cu^2+}\] oxidises \[\ce{I^-}\] to iodine.

पर्याय

  • Both assertion and reason are true, and reason is the correct explanation of the assertion.

  • Both assertion and reason are true but reason is not the correct explanation of assertion.

  • Assertion is not true but reason is true.

  • Both assertion and reason are false.

MCQ
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उत्तर

Both assertion and reason are true, and reason is the correct explanation of the assertion.

Explanation:

All halogens combine with copper to form copper halides except iodine. The reason behind this is that \[\ce{Cu^2+}\] oxidises iodide (-1) to iodine (0). Therefore, \[\ce{Cu^2+}\] iodide does not exist .Both the statements assertion and reason are correct and reason is the correct explanation of assertion.  

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पाठ 8: The d-and f-Block Elements - Multiple Choice Questions (Type - I) [पृष्ठ ११४]

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एनसीईआरटी एक्झांप्लर Chemistry Exemplar [English] Class 12
पाठ 8 The d-and f-Block Elements
Multiple Choice Questions (Type - I) | Q 59 | पृष्ठ ११४

संबंधित प्रश्‍न

How would you account for the following? 

Transition metals exhibit variable oxidation states.

 


Why +2 oxidation state of manganese is more stable?


Account for the following: 

Cr2+ is a strong reducing agent.


Account for the following:

Cu+2 salts are coloured, while Zn2+ salts are white.


`E_((M^(2+)/M)`

Cr Mn Fe Co Ni Cu
-0.91 -1.18 -0.44 -0.28 -0.25 -0.34

From the given data of E0 values, answer the following questions :

(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive

(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements

(3) Which is the stronger reducing agents Cr2+ or Fe2+ ? Give Reason.


Account for the following:

E° value for the Mn3+/Mn2+ couple is much more positive than that for Cr3+/Cr2+.


How would you account for the following:

Of the d4 species, Cr2+ is strongly reducing while manganese (III) is strongly oxidising.


Give reason for the following:

The transition metals generally form coloured compounds.


Maximum oxidation state is shown by ____________.


Metallic radii of some transition elements are given below. Which of these elements will have highest density?

Element \[\ce{Fe}\] \[\ce{Co}\] \[\ce{Ni}\] \[\ce{Cu}\]
Metallic radii/pm 126 125 125 128

Highest oxidation state of manganese in fluoride is \[\ce{+4 (MnF4)}\] but highest oxidation state in oxides is \[\ce{+7 (Mn2O7)}\] because ______.


Why EΘ values for Mn, Ni and Zn are more negative than expected?


Mention the type of compounds formed when small atoms like H, C and N get trapped inside the crystal lattice of transition metals. Also give physical and chemical characteristics of these compounds.


Read the passage given below and answer the following question.

Are there nuclear reactions going on in our bodies?

There are nuclear reactions constantly occurring in our bodies, but there are very few of them compared to the chemical reactions, and they do not affect our bodies much. All of the physical processes that take place to keep a human body running are chemical processes. Nuclear reactions can lead to chemical damage, which the body may notice and try to fix. The nuclear reaction occurring in our bodies is radioactive decay. This is the change of a less stable nucleus to a more stable nucleus. Every atom has either a stable nucleus or an unstable nucleus, depending on how big it is and on the ratio of protons to neutrons. The ratio of neutrons to protons in a stable nucleus is thus around 1 : 1 for small nuclei (Z < 20). Nuclei with too many neutrons, too few neutrons, or that are simply too big are unstable. They eventually transform to a stable form through radioactive decay. Wherever there are atoms with unstable nuclei (radioactive atoms), there are nuclear reactions occurring naturally. The interesting thing is that there are small amounts of radioactive atoms everywhere: in your chair, in the ground, in the food you eat, and yes, in your body.

The most common natural radioactive isotopes in humans are carbon-14 and potassium-40. Chemically, these isotopes behave exactly like stable carbon and potassium. For this reason, the body uses carbon-14 and potassium-40 just like it does normal carbon and potassium; building them into the different parts of the cells, without knowing that they are radioactive. In time, carbon-14 atoms decay to stable nitrogen atoms and potassium-40 atoms decay to stable calcium atoms. Chemicals in the body that relied on having a carbon-14 atom or potassium-40 atom in a certain spot will suddenly have a nitrogen or calcium atom. Such a change damages the chemical. Normally, such changes are so rare, that the body can repair the damage or filter away the damaged chemicals.

The natural occurrence of carbon-14 decay in the body is the core principle behind carbon dating. As long as a person is alive and still eating, every carbon-14 atom that decays into a nitrogen atom is replaced on average with a new carbon-14 atom. But once a person dies, he stops replacing the decaying carbon-14 atoms. Slowly the carbon-14 atoms decay to nitrogen without being replaced, so that there is less and less carbon-14 in a dead body. The rate at which carbon-14 decays is constant and follows first order kinetics. It has a half-life of nearly 6000 years, so by measuring the relative amount of carbon-14 in a bone, archeologists can calculate when the person died. All living organisms consume carbon, so carbon dating can be used to date any living organism, and any object made from a living organism. Bones, wood, leather, and even paper can be accurately dated, as long as they first existed within the last 60,000 years. This is all because of the fact that nuclear reactions naturally occur in living organisms.

Researchers have uncovered the youngest known dinosaur bone, dating around 65 million years ago. How was the age of this fossil estimated?


A metallic ion 'M' reacts with chloride ion to form white precipitate which is readily soluble in aqueous ammonia. Identify 'M'?


Which of the following ions has the maximum magnetic moment?


Why are all copper halides known except that copper iodide?


In the ground state of atomic Fe (Z = 26), the spin-only magnetic moment is ______ × 10-1 BM.
(Round off to the nearest integer).

[Given: `sqrt3 = 1.73, sqrt2 = 1.41`]


The disproportionation of \[\ce{MnO^{2-}_4}\] in acidic medium resulted in the formation of two manganese compounds A and B. If the oxidation state of Mn in B is smaller than that of A, then the spin-only magnetic moment (µ) value of B in BM is ______. (Nearest integer)


Match List-I with List-II.

List-I List-II
A. Haber process I. Fe catalyst
B. Wacker oxidation II. PdCl2
C. Wilkinson catalyst III. [(PPh3)3RhCl]
D. Ziegler catalyst IV. TiCl4 with Al(CH3)3

Choose the correct answer from the options given below:


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