Sunday, July 31, 2022

Some More Frequently Asked Question on JustAsk - Ribblu.com

 

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who are included in lab our force

give the meaning of work force

define worker population ratio

who is casual wage laborer

how will you know whether a worker is worker in the informal sector

why are regular salaried employees more in urban areas than in rural areas

why do we diffrentiate between economic activity and production activity

what are fluids give examples

solids are rigid why

how are solids classified

why do crystalline solids are anisotropic nature and amorphous solid are isotropic in nature

why do crystalline solids are anisotropic nature and amorphous solid are isotropic in nature 1

define the term crystal lattice

what is a unit cell

what is square close packing

define a void b coordination number

what is the packing efficiency in

what is the meaning of term defect with reference to crystal

name the types of point defect

what are f centres

give an example which shows both frenkel and schottky defect

define the term doping

what is the meaning of 13 15 compounds

name an element which can be added to silicon to give a i p type semiconductor ii n type semiconductor

what is the difference between ferromagnetic and paramagnetic substances

the window panes of the old buildings are thick at the bottom why

the stability of a crystal is reflected in the magnitude of its melting point explain

graphite is soft and good conductor of electricity explain

ionic solids are good conductors in molten state and in aqueous solutions but not in solid state why

name three types of cubic unit cells

what is the no of octahedral and tetrahedral voids present in a lattice

define two main types of defects

excess of lithium makes licl crystal pink explain

define the terms intrinsic semiconductor and extrinsic semiconductor

give two application of p type and n type semiconductors

classify each of the following as being either a p type or an n type semiconductor i ge doped with in ii b doped with si

define the term amorphous give a few examples of amorphous solids

what makes a glass different from a solid such as quartz under what conditions could quartz be converted into glass

how are crystalline solids classified on the basis of nature of bonding explain with examples

stability of a crystal is reflected in the magnitude of its melting point comment collect melting 
points of solid water ethyl alcohol diethyl ether and methane from a data book what can you say about the intermolecular forces between these molecules

explain the schottky defect terms with suitable examples

explain the frenkel defect terms with suitable examples

explain the interstitials terms with suitable examples

explain the f centres terms with suitable examples

define the term solubility

what is the effect of pressure on solubility of a gas

state henrys law

state raoults law

what are the factors on which vapour pressure depends

the vapour pressure of solvent gets lowered when a non volatile solute is added to it why

name two ways by which vapour pressure of a liquid can be lowered

definesolution

how does change in temperature changes the molarity and molality values

define the term colligative properties

what are the possible deviations from ideal behaviors

give one example of each deviation

how much urea molar mass 60 gmol should be dissolved in 50g of water so that its vapour pressure at room temperature is reduced by 25

why is the boiling point elevated when a non volatile solute is dissolved in a liquid

what happens when red blood cells are placed in 01 nacl solution

how is osmotic pressure of a solution related to its concentration

when does the measurement of colligative property leads to abnormal molecular mass

when is the value of i less then unity

what role does the molecular interaction play in a solution of alcohol and water

give an example of solid solution in which the solute is a gas

define the term azeotrope

define the term solution how many types of solutions are formed write briefly about each type with an example

can you store agcl solution in zinc pot

define the term standard electrode potential

can an electrochemical cell act as electrolytic cell how

single electrode potential cannot be determined why

what is she what is its electrode potential

what is an electrochemical series how does it predict the feasibility of a certain redox reaction

give some uses of electrochemical cells

state the factors that affect the value of electrode potential

state kohlrauschs law

what is meant by faradays constant

why is the voltage of a mercury cell constant during its working

what are fuel cells

what do you understand by corrosion

name two metals that can be used for cathodic protection of iron

arrange the following metals in the order in which they displace each other from the solution of their salts al cu fe mg and zn

suggest two materials other than hydrogen that can be used as fuels in fuel cells

suggest a list of metals that are extracted electrolytically

what are the factors on which conductivity of an electrolyte depend

the conductivity of metals decreases while that of electrolytes increases with increases in temperature why

state faradays laws of electrolysis

silver is deposited on a metallic vessel by passing a current of 02 amps for 3 hrs calculate the weight of silver deposited at mass of silver 108 amu f 96500 c

what do you mean by primary and secondary battery

rusting of iron is quicker in saline water than in ordinary water explain

why does the conductivity of a solution decrease with dilution

is rate of reaction always constant

can order of reaction be zero give example

what do you understand by rate law expression

is it possible to determine or predict the rate law theoretically by merely looking at the equation

define the term chemical kinetics

define rate of reaction and the factors affecting the rate of reaction

what is the effect of catalyst on rate constant

how is activation energy affected on adding a catalyst

what do you mean by the term collision frequency

what is the drawback of collision theory

how does the number of collisions change on increasing the temperature

there is no bar on the no of collisions among the reaching species why most of the reactions do not take place under normal conditions

define the terms i order of a reaction ii molecularity of a reaction

what are elementary and complex reactions

in the expression of rate of reaction in terms of reactants what is the significance of negative sign

what is the use of integrated rate equation

how does collision theory explain formation of products in a chemical reaction

mention the factors that affect the rate of a chemical reaction

what do you mean by the term adsorption

why do finely divided solids act as good adsorbents

name the factors which influence the extent of adsorption of a gas on solid

what is adsorption isotherm

what are positive and negative catalysts explain

what do you mean by the term promoter give an example

what is the optimum temperature and ph for enzyme catalysed reactions

what are colloids

what is the range of particle size in colloids

give two examples of solid sol and gel

colloid is a state not a substance explain

state hardy schulze rule

what is a protective colloid

what is flocculation

what is the role of desorption in the process of catalysis

what is demulsification name two demulsifiers

why do the solution of organic dye turns colourless when charcoal is added

define the term desorption

name the two types of adsorptions

adsorption is an exothermic process explain

explain the mechanism of adsorption

define the terms catalysis and catalyst

what is meant by activity and selectivity of a catalyst

what is shape selective catalysis give an example of shape selective catalyst

write characteristics of enzyme catalysed reactions

give two examples of reactions catalysed by zeolites

what are associated colloids give an example

what is cmc and krafts temperature

define the term peptization

how is a colloidal solution purified by dialysis

what is observed when light is passed through a colloidal solution

define the terms a brownian movement b electrophoresis

give three applications of colloidal solutions

what are the two types of emulsions

how does an emulsifying agent work give an example of emulsifying agent

write any two characteristics of chemisorption

why does physisorption decrease with the increase of temperature

why are powdered substances more effective adsorbents than their crystalline forms

what modification can you suggest in the hardy schulze law

why is it essential to wash the precipitate with water before estimating it quantitatively

give reason why a finely divided substance is more effective as an adsorbent

what do you understand by activation of adsorbent how is it achieved

discuss the effect of pressure and temperature on the adsorption of gases on solids

what are emulsions what are their different types give example of each type

describe some features of catalysis by zeolites

what is shape selective catalysis

give four uses of emulsions

comment on the statement that colloid is not a substance but a state of substance

explain modern theory of heterogeneous catalysis

distinguish between the meaning of the terms adsorption and absorption give one example of each

explain the terms with suitable examples i alcosol ii aerosol iii hydrosol

what role does adsorption play in heterogeneous catalysis

what are lyophilic and lyophobic sols give one example of each type why are hydrophobic sols easily coagulated

what is the difference between multimolecular and macromolecular colloids give one example of each how are associated colloids different from these two types of colloids

what is pig iron

what is cast iron

what is wrought iron

what is added as flux in extraction of iron

why is cryolite used during extraction of aluminum

how is copper extracted from low grade ores

state one limitation of ellingham diagrams

give an example of extraction based on oxidation reduction

which method is used for refining of silicon or gallium

what is the principle behind zone refining

give the requirements for vapour phase refining

name the common elements present in the anode mud in electrolytic refining of copper why are they so present

what is meant by the term chromatography

what criterion is followed for the selection of the stationary phase in chromatography

how is cast iron different from pig iron

what is the principle behind chromatography name some types of chromatographic techniques

write the elements of group 15

the atomic radii increases considerably from n to p but very little increase is observed from as to bi why

give reason for the following the first ionization enthalpy of 15th group elements is higher than 16th group elements

what are the common oxidation states of this group

what is the maximum covalence shown by n

bi v is a stronger oxidizing agent than biiii why

ammonia is a lewis base why

ammonia has higher boiling and melting points than expected why

write two uses of chlorine

write the characteristics of pure ozone

at what concentration ozone is harmful

which aerosols and oxides deplete ozone layer

write the members of 16 group

enlist some uses of dioxygen

which of the following does not react with oxygen directly zn ti pt fe

explain why fluorine forms only one oxoacid hof

write two uses of dinitrogen

why are pentahalides more covalent than trihalides

give two examples to show the anomalous behaviour of fluorine

why is helium used in diving apparatus

why does nitrogen show catenation properties less than phosphorus

which aerosols deplete ozone

explain why inspite of nearly the same electronegativity oxygen forms hydrogen bonding while chlorine does not

why are halogens coloured

why do noble gases have comparatively large atomic sizes

list the uses of neon and argon gases

what are the factors that decide the ionization potential

name the two series of f block

the chemistry of actionoids is more complicated than lanthanoids why

what is the most common oxidation state of lanthanoids and actionoids

actionoid contraction is more than lanthanoid contraction give reason

what is the composition of mischmetall give its one use

actionoids show larger number of oxidation states than lanthanoids why

give an explanation for the catalytic properties shown by transition metals

write some characteristics of interstitial compounds

what is the lanthanoid contraction what are its causes and consequences

why is the highest oxidation state of a metal exhibited in its oxide or fluoride only

actinoid contraction is greater from element to element than lanthanoid contraction why

what is lanthanoid contraction what are the consequences of lanthanoid contraction

what are the characteristics of the transition elements and why are they called transition elements which of the d block elements may not be regarded as the transition elements

what are the different oxidation states exhibited by the lanthanoids

what are interstitial compounds why are such compounds well known for transition metals

what are alloys name an important alloy which contains some of the lanthanoid metals mention its uses

what are inner transition elements decide which of the following atomic numbers are the atomic numbers of the inner transition elements 29 59 74 95 102 104

the chemistry of the actinoid elements is not so smooth as that of the lanthanoids justify this statement by giving some examples from the oxidation state of these elements

what do you understand by stability of a complex and instability constant of coordination compounds

how is excess of copper and iron removed from body

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