Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: R

There are no items in this cart.
Continue Shopping
Get instant 20% OFF on Online Material.
coupon code: MOB20 | View Course list

Get extra R 650 off


1.Is the structure of water not cage-like?If its so then how the volume increases when it changes into ice?And if not, then why its not cage like?

2.Anything changes from liquid to solid when its molecule comes closer but that's not the case with water.Explain.

Please answer these.These are my conceptual doubts and not any question I find somewhere in book or so.

I'll surely approve all correct answers


6 years ago


Answers : (1)


Dear nitin,

A molecule of water consists of two hydrogen atoms joined to an oxygen atom by covalent bonds.

Structure of water molecule

The oxygen atom has six electrons (1s2 2s2 2p4) in its outermost shell. The 's' and 'p' orbitals of the valence shell are sp3 hybridized to form four sp3 hybrid orbitals oriented tetrahedrally around the oxygen atom. Two of the hybrid oribtals are singly occupied, while the lone pairs of electrons occupy the other two. Each singly occupied sp3 orbital overlaps with the half-filled 1s orbital of 'H' atom. Thus, oxygen is bonded to the two hydrogen atoms by two O-H covalent bonds, and there are two lone-pairs of electrons on the oxygen atom. Due to the presence of two lone-pairs of electrons on the O atom, the H-O-H bond angle is 104.5°, which is slightly less than the tetrahedral angle of 109°28'. Therefore, the structure of water molecule is an angular or bent structure.

Polarity of water molecule

Oxygen is more electronegative than hydrogen, being only second to fluorine in its electronegativity. Its high electronegativity causes the oxygen atom to pull the shared pairs of electrons more towards itself. As a result, the O-H bond acquires polarity. Since the two O-H bonds in water are inclined at an angle, hence the net dipole moment of water molecule is not zero. The actual dipole moment of water molecule is 1.84 debye, (denoted as D) is the unit of dipole moments.

Structure of water molecule in the liquid state

In liquid water, water molecules are held together by intermolecular hydrogen bonds. Each oxygen atom can form two hydrogen bonds utilizing both the lone pairs on it. Experimental studies suggest that liquid water consists of aggregates of varying number of water molecules held together by hydrogen bonds and 'free' water molecules in a dynamic equilibrium. The aggregates continually forming, collapsing and reforming. Thus, in liquid water, the equilibrium

equilibrium of liquid water

Hydrogen bonding has very profound effect on the properties of water.

bonding in hydrogen

Structure of water in solid state (ice)

Depending on the conditions for freezing of water, the solid form of water i.e., ice, can exist in different crystalline forms. In 'normal' hexagonal ice, four other oxygen atoms tetrahedrally surround each oxygen atom. One hydrogen atom lies in between each pair of oxygen atoms. Thus, each and every hydrogen atom is covalently bonded to a oxygen atom and linked to another oxygen atom by a hydrogen bond. This arrangement leads to a packing with large open spaces and results in a lower density of ice than that of liquid water.

When ice melts some of the hydrogen bonds are broken and the water molecules become more closely packed. It results in an increase in the density of water above its melting points (273 K). Density of water attains a maximum value of 1 g/mL at 277 K (4°C); above 277 K, the density decreases due to the normal temperature effects.

Structure of water in solid state

Fig: 11.4 - Structure of normal hexagonal ice

There is one hydrogen along each oxygen - oxygen axis closer to one of the two oxygen atoms.

Significance of lower density of ice in nature

Ice floats on water because of its lower density when compared to liquid water. During winter, this floating block of ice prevents or delays the freezing of the underlying water. Thus, when the temperature falls below zero degree Celsius, the upper layer of water in most aquatic bodies such as lakes etc., get frozen, but the underlying water remains liquid. This enables the aquatic life to survive during the winter months.

Please feel free to ask your queries here. We are all IITians and here to help you in your IIT JEE preparation.

All the best.

Win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.

Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar  respectively : Click here to download the toolbar..


Askiitians Expert

Sagar Singh

B.Tech, IIT Delhi

6 years ago

Post Your Answer

Other Related Questions on Physical Chemistry

Give a daily life example for adiabatic system and isolated system.
@ maradana adiabatic system is a system in which no heat will be sent in or out , so, as an real life example u can take the example of thermoflask , of hotpot , in which the stored...
Umakant biswal one month ago
what is the oxidation state of sulphur in H 2 S 2 O 8, Na 2 S 4 O 8 and Na 2 S 2 O 3.
@ bhavika in H2S2O8, since 2 oxygen is forming the peroxide linkage here , so, the o.n of sulpher will be +6 . and in the 2 nd case NA2S4O8 , in thaat case take sulpher o.n to be x after...
Umakant biswal 3 months ago
You no longer have to wait desperately for someone to help resolve your doubt. You can chat with IITians live, 24/7 (even at 3AM!) and get your doubt resolved instantly. Try the HashLearn...
Ankit 3 months ago
u need to remember that which structure have peroxide linkage and which structure have not , there are only some exception with peroxide linkage , go through the ncert redox reaction...
Umakant biswal 3 months ago
thermodynamics,chemistry question is attached....................................
U=nc(at const. vol.)dt=5000J, but how come the answer is 6000J.........................................................
Naveen Shankar one month ago
The system is working at constant pressure. hence Change in internal energy is given as: U = F/2 nRt + (F/2+1)nRt here t is change in temp from final to initial. F is degree of freedom. n...
Vikas TU one month ago
S8 Molecule does not reacts with chemical reacts but Sulphour atom reacts chemical reactions why
S8 is a molecule . S is an atom , s8 just happens to be one of the molecule sulpher can form out of 8 sulpher atom . this means that it will not always be written as s8 in a chemical...
Umakant biswal one month ago
S8 is present in crown shaped form which makes the molecule stable and innert in nature. The innert nature is due to high electron density, which repells the other electrons and thus it...
KAUSTABH PAL one month ago
What are analgesics and food preservatives.........?
Analgesics are drugs that reduce or totally abolish pain without causing disturbances of nervous system. There are two types of analgesics i. Narcotic analgesics E.g.: Morphine ii....
SAI SARDAR 3 months ago
Analgesis is defined as the drugs that reduce or abolish pain without causing impairment of conciousness,mental confusion,incoordinationor paralysis or some other disturbances of nervous...
somprasad 3 months ago
An analgesic or painkiller is any member of the group of drugs used to achieve analgesia , relief from pain. Analgesic drugs act in various ways on the peripheral and central nervous...
Umakant biswal 3 months ago
All over nao2 what is among is. What nao2 separate is also found.
Already answered . Check twice please! NaO2 is called sodium superoxide which is obtained by treating Na2O2 that is sodium peroxide with O2 at high pressures. The Reaction goes like this:...
Vikas TU 14 days ago
View all Questions »

  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details
Get extra R 3,750 off

Get extra R 650 off

More Questions On Physical Chemistry

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details