10th Class Chapter 7 Chemistry Long Questions

Temporary and permanent hardness of water is removed by the flowing methods.

Method of removal of temporaray hardness:

Temporary hardnes of water is removed by following method, By boiling, clak’s method

Boiling:

Temporary hardness of water is recovered removed by boiling water due to boiling calcium and magnesium bicarbonate are converted into insoluble carbonates of calcium and magnesium.

Chemical reaction: Ca(HCO3)2_______Ca Co3+H2O+Co2

Clak’s ,Methods:

A chemical methods to remove temporaray hardnesss is by addition of slaked time Ca(OH)2 is called clak’s method.

Chemical reaction:Ca (HCO3)2+ Ca( OH)2_______ 2CaCo3+2H2 O1

Water is the universal solvent because it can dissolve almost all of the minerals due tityo the two unique properties of water.Polarity of water molecule Exceptional hydrogen bonding.

Polarity of water molecule polar nature:

Water molecules has polar structure the electronogativity different between the atoms of oxygen and hydrogen make water polar in behavior.

Solubility of polar substances:

All polar substance are soluble in water because positive end of the substance attrached by the negative of the water while negative end of the substance attracted by the positive end (HS+) o f water molecule.

Extensive hydrogen bonding:

Water molecules consists of oxygen and hydrogen atoms water molecules contain two O-H bonds and two long pair.

Neutral:

Water is neutral in nature and has no effect on litmus.

Freezing point and melting point:

Water freeze at OC° while boils at 10OC at sea level.

Density:

Water has maximum density at 4C° which is 1gcm3

Excellent solvent:

Water is an excellent solvent for ionic as well as for molecular compounds.

Heat capacity:

Heat capacity of water is about 4,2IG-1 K-1, It is six times greater than of rocks

Cholera:

Cholera is an acute infection caused by the bacteria vibrius cholera which may be found in water contaminated by human feaces.

Cryptosporidium:

Water borne micro organisms that causes gastrointestinal illness including diarrhea and vomiting.

Polarity of water molecules exceptional hydrogen bonding ability polar nature of water molecule has polar structure one end of the molecule is paritially negative because of electronagetive defference between oxygen and hydrogen atoms ,all other polar substance are soluble in water because the positive end of the substance is attracted by the negative and (OS) of the water and negative end of the substance is attracted by the positive end (HS+) of the water.

Exlensive hydrogen bonding ability water molecule is compose d o oxygen an d hydrogen atoms because of two O-H bonds and two lone pairs one H2O molecule can form hydrogen bonding with four other H2O molecule.

Sodium zeolite removes calcium and magnesium of hard water so makes it soft.

Na2Zeolite+CaSo4_______Cazeolite +NaSo4

Dipole –dipole force are responsible for dissolving polar substance in water.

Dissolved salts of Mg2+ and Ca2+ with CL-,So4-2,HCO3-1 and CO3-2 causes hardness in water.

CaCO3+H2O+CO2_______Ca (HCO3)2

Sugar and alcohols have polar end i.e O5___HS+ group these substance are soluble in water under due to hydrogen bonding.

Limestone (Caco3) in insloluble in water but small quantity of limestone is soluble in water in the presence of CaCo3+CO+H2O_____Ca(HCO3)

Temporary hard water causes stomach disorder insoluble reduce the efficiency of engine and boiler burst up .

It makes water unfit for qualite life they cause diseases by microbes the phosphats salts present in detergents cause rapid grouth of algae.

Those substance that can be decomposed by micro organism like bacteria are called biodegradable substance that cannot be decomposed by ion is or organism like bacteria are called non biodegradable.

Because they kill or control the growth of pests pests may be weeds herbs fungi and viruses.

Water pollution is a contamination of water,bodies water bodies include lakes rivers ocears and ground water it occurs when pollutouts are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds.

A chemical methods to remove temporary hardness is by addition of slaked lime (CACOH2) Is called clark’s method.

Waste particles which is discharged by industrial units is called industrial waste.

The hard layer of calcium and magnesium carbonates deposite d in industrial scale.

Fertilizers ar used to make up the deficiency of nitrogen phosphorous of soil.

Pests include weeds herbs insects fungi and viruses.

Water is the universal solvent because it can dissolve almost all the minerals

Water is made up of hydrogen ion (H+) linked to hydroxyl ions (OH) to form water (H2O).

Temporary hardness is cause d by the presence of dicarbonates of calcium and magnesium.

A chemical methods to remove temporary hardness is by addition of slaked lime (Ca(oh)2) is called clark’s method.

They deteriorate to quality of water they reduce the quantity of dissolve d oxygen.

It is not water which produces good lather with soap it does not give curd it is that type of water which does not produce good lather with soap it gives curds with soap.

The hard layer of calcium and magnesium carbonates deposited in industrial boiler scale.

Water borne diseases are those diseases that spread because of drinking polluted water provision of safe water disposal of sewage control to toxic chemicals.