Give reason for the appearance of colour in alkali metal halides.

Give reason for the appearance of colour in alkali metal halides. 
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1 Answer

Answer :

Due to F-centres.
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Give reason for the colour imparted to the flame by alkali metals

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Alkali metal salt "X" gives a pale violet colour in flame test "X" is :

Description : Alkali metal salt "X" gives a pale violet colour in flame test "X" is :

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Metal sulphides occur mainly in rocks and metal halides in lakes and seas. Explain.

Description : Metal sulphides occur mainly in rocks and metal halides in lakes and seas. Explain.

Last Answer : Ans.: Metal halides being soluble in water, get dissolved in rain water and are carried to lakes and seas during weathering of rocks. On the otherhand, metal sulphides being insoluble are left behind in the rocks as residue.

Give point of resemblance of hydrogen with alkali metal.

Description : Give point of resemblance of hydrogen with alkali metal.

Last Answer : Ans: 1 like alkali metals hydrogen also has one electron in its valence shell 2 like alkali metals hydrogen loses its only electron to form proton(H+) 3 like alkalis metals hydrogen ... the same way as alkali metals are librated at the cathode during the electrolysis of their fused halides

Give reason .the compounds of alkaline earth metals are less ionic than alkali metals

Description : Give reason .the compounds of alkaline earth metals are less ionic than alkali metals

Last Answer : Ans This is due to increased nuclear charge and smaller size.

Give reason for the following: (i)alkali metals do not occur free in nature. (ii)alkali metals have low I .E. (iii)LiI is more soluble than KI in ethanol.

Description : Give reason for the following: (i)alkali metals do not occur free in nature. (ii)alkali metals have low I .E. (iii)LiI is more soluble than KI in ethanol.

Last Answer : Ans.(i)They are highly reactive in natur (ii) Because of large atomic size. (III)LiI is more covalent in character than KI

Give reason .the melting point and boiling point of alkali metals are low

Description : Give reason .the melting point and boiling point of alkali metals are low 

Last Answer : The melting and boiling points of the alkali metals are low indicating weak metallic bonding due to the presence of only a single valence electron in them. 

Give reason .the compounds of alkaline earth metals are less ionic than alkali metals

Description : Give reason .the compounds of alkaline earth metals are less ionic than alkali metals

Last Answer : This is due to increased nuclear charge and smaller size. 

Give reason for the higher melting point and boiling point of alkali earth metals than alkali metals.

Description : Give reason for the higher melting point and boiling point of alkali earth metals than alkali metals. 

Last Answer : The melting and boiling points of these metals are higher than the corresponding alkali metals due to smaller sizes. 

What is alkali metal ?

Description : What is alkali metal ?

Last Answer : The first class elements of a periodic table are called alkali metals.

An element with an atomic number of 17 is - (1) an alkali metal (2) a rare gas (3) a halogen gas (4) a transition metal

Description : An element with an atomic number of 17 is - (1) an alkali metal (2) a rare gas (3) a halogen gas (4) a transition metal

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Arrange the following in order of the increasing covalent character : MCl,MBr,MF,MI ( Where M=alkali metal)

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Last Answer : Ans. MF < MCI < MB < MI

when an alkali metal dissolves in liquid ammonia, the solution can acquire different colors. Explain .

Description : when an alkali metal dissolves in liquid ammonia, the solution can acquire different colors. Explain .

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Which alkali metal has the highest ionic radii ?

Description : Which alkali metal has the highest ionic radii ?

Last Answer : Ans.Cs.

Which alkali metal will have highest hydration enthalpy ?

Description : Which alkali metal will have highest hydration enthalpy ?

Last Answer : Ans. Li

When a cation is highly polarizing ? Which alkali metal cation has the highest polarizing power ?

Description : When a cation is highly polarizing ? Which alkali metal cation has the highest polarizing power ?

Last Answer : Ans. A cation is highly polarizing if its charge/size ratio is very high.Li+ has the highest polarizing power .

Name the alkali metal which forms only the normal oxide on heating with air ?

Description : Name the alkali metal which forms only the normal oxide on heating with air ?

Last Answer : Ans. Li.

Name the alkali metal which shows diagonal relationship with Mg?

Description : Name the alkali metal which shows diagonal relationship with Mg?

Last Answer : Ans.Li

Within a given period of the periodic table, the element with the lowest ionization energy is: w) transition metal x) alkali metal y) halogen z) noble gas

Description : Within a given period of the periodic table, the element with the lowest ionization energy is: w) transition metal x) alkali metal y) halogen z) noble gas

Last Answer : ANSWER: X -- ALKALI METAL

What colour does the universal indicator turn when the alkali is neutralized?

Description : What colour does the universal indicator turn when the alkali is neutralized?

Last Answer : blue

What is the reason for the increasing stability of peroxide & superoxide of alkali metals down the group?

Description : What is the reason for the increasing stability of peroxide & superoxide of alkali metals down the group? 

Last Answer : On combustion in excess of air, lithium forms mainly the oxide, Li2O (plus some peroxide Li2O2), sodium forms the peroxide, Na2O2 (and some superoxide NaO2) whilst potassium, rubidium and ... are also paramagnetic. Sodium peroxide is widely used as an oxidising agent in inorganic chemistry.  

Silver halides are used in photographic plates because they are - (1) oxidised in air (2) soluble in hyposolution (3) reduced by light (4) totally colourless

Description : Silver halides are used in photographic plates because they are - (1) oxidised in air (2) soluble in hyposolution (3) reduced by light (4) totally colourless

Last Answer : (3) reduced by light Explanation: The light-sensitive chemicals used in photographic film and paper are silver halides. Silver halides are used in photographic film and photographic paper, including ... - meaning that it can undergo development which turns the entire crystal into metallic silver.

Why the presence of a base is essential in the ammonolysis of alkyl halides ?

Description : Why the presence of a base is essential in the ammonolysis of alkyl halides ?

Last Answer : During ammonolysis of alkyl halides, the acid liberated during the reaction combines with the amine formed to form amine salt. To liberate free amine from the amine salt, a base is needed.

When ammonia is added to an alkyl halide, in the presence of base : (a) primary amines form (b) amides form (c) nitrated alkyl halides form (d) quaternary ammonium salts form

Description : When ammonia is added to an alkyl halide, in the presence of base : (a) primary amines form (b) amides form (c) nitrated alkyl halides form (d) quaternary ammonium salts form

Last Answer : primary amines form

Aryl halides are less reactive towards nucleophilic substitution as compared to alkyl halides due to (a) Inductive effect (b) Resonance stabilization (c) Tautomerism (d) Stereoisomerism

Description : Aryl halides are less reactive towards nucleophilic substitution as compared to alkyl halides due to (a) Inductive effect (b) Resonance stabilization (c) Tautomerism (d) Stereoisomerism

Last Answer : Resonance stabilization

Alkyl halides react with ammonia in the presence of base to form : (a) primary amines(b) nitrated alkyl halides(c) amides(d) quaternary ammonium salts

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Grignard reagents do not show any reaction with (a) Alkoxyalkanes (b) Alkanones (c) Alkyl alkanoates (d) Acyl halides

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Last Answer : Alkoxyalkanes

Which of the following halides is least reactive in an E2 reaction with sodium methoxide? (a) (CH3)3CCH2I (b) (CH3)2CHCHICH3 (c) (CH3)2CHCH2Br (d) (CH3)2CHCH2Cl

Description : Which of the following halides is least reactive in an E2 reaction with sodium methoxide? (a) (CH3)3CCH2I (b) (CH3)2CHCHICH3 (c) (CH3)2CHCH2Br (d) (CH3)2CHCH2Cl

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Which of the following halides is most reactive in an E2 reaction with sodium methoxide? (a) (CH3)3CCH2I (b) (CH3)2CHCHICH3 (c) (CH3)2CHCH2Br (d) (CH3)2CHCH2C

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Last Answer : (CH3)2CHCHICH3

Which of the following statements concerning SN2 reactions of alkyl halides is not correct? (a) The rate of reaction depends on the concentration of the nucleophile. (b) The rate of reaction depends on the concentration of the alkyl halide. (c) The rate of reaction of a particular alkyl bromide depends on the steric accessibility of the carbon of the C-Br bond. (d) All alkyl iodides react more rapidly than all alkyl chlorides

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Which of the following is not correct concerning substitution and elimination reactions of alkyl halides? (a) The electrophile replaces the leaving group. (b) Compounds containing electron-donating groups bonded to an sp3 hybridized carbon undergo substitution and elimination reactions. (c) The electronegative atom is replaced by another atom or group in substitution reactions. (d) (a) and (b)

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Which alkyl halides react most readily by nucleophilic substitution? (a) CH3CH2Cl (b) CH3CH2I (c) CH3CH2Br (d) CH3CH2F

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Last Answer : CH3CH2I

Alkyl halides undergo (a) Electrophilic substitution reactions (b) Electrophilic addition reactions (c) Nucleophilic substitution reactions (d) Nucleophilic addition reactions

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Whose name is given to alkylmagnesium halides: w) Victor Grignard x) Daniel Rutherford y) Dmitri Mendeleev

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Silver halides are used in photographic plates because they are (1) oxidised in air (2) soluble in hyposolution (3) reduced by light (4) totally colourless

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Last Answer :  reduced by light

The phenomenon of light associated with the appearance of blue colour of the sky is – (1) Interference (2) Reflection (3) Refraction (4) Scattering

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In the case of peppered moth (Biston betularia) the black-coloured form became dominant over the light-coloured form in England during industrial revolution. This is an example of (a) appearance of the darker coloured individuals due to very poor sunlight (b) protective mimicry (c) inheritance of darker colour character acquired due to the darker environment (d) natural selection whereby the darker forms were selected.

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Last Answer : (d) natural selection whereby the darker forms were selected.

Which of the following hydrogen halides react with `AgNO_3` to give a precipitate that dissolves in hypo solution ? (I)HCl (II)HF (III)HI (IV)HBr

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What is the most electrically positive and active metal of the alkali metal period ?

Description : What is the most electrically positive and active metal of the alkali metal period ?

Last Answer : Alkali metal is the most electrically positive and active metal of all time .

None Metal Of alkali With Reaction By No ?

Last Answer : Copper ' Of alkali With Reaction By No.

Which of the following alkali metal ions has the lowest ionic mobility in aqueous solutions?

Description : Which of the following alkali metal ions has the lowest ionic mobility in aqueous solutions?

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The ease of adsorption of the hydrated alkali metal ions on ion-exchange resins follows the order:

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Alkali metal hydrogen fluorides have a formula `M[HF_2]`. They are found to contain a linear symmetrical anion having an overall F—H—F distance of 2.2

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`Mf + XeF_(4) rarr M^(+) A^(-) (M^(+)-` alkali metal cation) The state of hybridisation of the central atom in A and sphere of the species are:

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Why alkali metal have low ionization energy?

Description : Why alkali metal have low ionization energy?

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Why alkali metal have low ionization energy?

Description : Why alkali metal have low ionization energy?

Last Answer : Ionization energy is the energy required to remove an electronfrom an atom or ion. Low ionization energy indicates that it takesless energy to remove an electron from the atom. The alkali ... are more and more electrons in theoutermost energy level, requiring more energy to remove anelectron.

Which element is in the alkali metal family?

Description : Which element is in the alkali metal family?

Last Answer : Lithium (Li) APEX

Which of the following properties is not true for an alkali metal? (a) Low electronegativity (b) Low ionisation energy (c) Low atomic volume (d) Low density

Description : Which of the following properties is not true for an alkali metal? (a) Low electronegativity (b) Low ionisation energy (c) Low atomic volume (d) Low density

Last Answer : Ans:(c)

The solubility of the alkali metal carbonates (a) Decreases as we go down the group (b) Increases as we go down the group (c) Increases at first and then decreases (d) Does not show regular variation

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Last Answer : Ans:(b)

Most abundant alkali metal is?

Description : Most abundant alkali metal is?

Last Answer : Sodium (Na)