allylic substitution definition

The hydrogen atom of any saturated carbon atom adjacent to a double bond ,for example the hydrogen atoms of the methyl group of propene ,are called allyilic hydrogen atoms and any reaction in which an allylic H atom is replaced is called an allylic substitution. For example,

ideal solution

ideal solution definition:
                                          a solution is said to be an ideal solution if its constituents follow roults law under all conditions. i.e,
p =x  p* .where p is the partial vapour
  i     i   i                i
pressure of the constituent i  whose amount fraction in this soloutin is x
                                                                 i

and p* is the corresponding vapour
         i
pressure of the pure component.
for this solution

       
{1} ∆H      =0 and ∆V      =0
            mix                 mix
{2} if solvent is A and solute is B then
A-A, A-B, B-B intersection must be same.

  ideal solution raoult’s law:
                                             French chemist raoult found that the ratio of the partial pressure of each component to its vapour pressure as a pure liquid ,
P  / P* is approximately equal to mole
 i       i
fraction of this component .it is known as raoult’s law
equation:
P=x P*
  i    i  i

Phase - definition of phase

Definition of  phase:A phase is define as any homogeneous and physically distinct part of a system which is separated from other part of a system by bounding surface.The term homogeneous means that system has identical physical properties and chemical composition throughout the whole of the system.
Number of phase: 
(1)for gas:there are one phase as they are completely misible in all proportion.
(2)for liquid: there are no of phase equal to the no of layer.for completely misible liquid the no of phase is one.
(3)for solid:In general every solid constitute is a single phase except when a solid solution is form.for solid solution the no of phase is 1.
No of component: The minimum no of independent chemical consititute by means of which each and every phase of the system can be expressed .Independent chemical constitute means whose conc can be varied independently of other constite of the system.
Degree of freedom: The degree of freedom of the system  can be expressed as the no of factor such as tempreture,pressure and concentration which can be varied  independently without altering the no of phase of the system.
Phase Rule:The various condition of equilibrium between phase such as no phase, no of  component,Degree of freedom can be correlated with one another with the help of a general rule ,known as a phase rule.Gibbs phase rule is 
[ F=C-P+2 ]

Viscosity –viscosity for gas

Viscosity for gas

If a gas flow in a tube it is seen that the velocity of the layer just touched in the tube is zero.It increase to the center.the velocity of center is maximum. So there must exist a velocity gradient.
It is due to the continuously movement of gas molecules. There is an interchange the molecules between to layer .as a result a part of momentum of one layer is pass over to another layer.so there happen a net decrease in relative velocity of a layer compare to another layer.So there must a internet friction whis is the viscosity of gas.To maintain uniform velocity gradient a force is applied to the direction of flow,which is the measurement of viscosity for gas.

Defination of viscosity with dimension and unit

we can define the viscosity as he tangential force required per unit area to maintain the unit velocity gradient, I.e, to maintain unit difference of velocity between two layers unit distance apart.

Basic idea about viscosity of liquid

we all know from basic idea that all liquid don't flow on same speed.such flow of water is greater than glycerol.there must be a internal friction which vary liquid to liquid.
for laminar flow  of an liquid in a tube the velocity of layer just in touch with the side of tube is zero.but velocity increase as we proceeds towards  center. the velocity of layer of the center is maximum.
thus there exist which is known as the velocity gradient between different layer of liquid.

This is happen for internuclear
attraction between molecules of two different layer.For inter nuclear attraction a   molecule moving in a layer tend to impede the flow of different molecule of  the adjacent faster layer.as a result the velocity of the faster layer decreases unless this decrease is prevented by applying the force towards forward direction. the velocity of faster moving layer going on decrease and ultimately it will become zero.at this state the liquid flowing stop.thud there is a tendency to decrease the relative motion as if there is a tangential force dragging backwards. this is viscus force. this is can be expressed in terms of tangential force which is needed to keep the speed of different layer constant.

একটি কবিতা পরুন নাম "দুঃখ কর্ম"

স্বপ্ন হতে আসে সুখ
সুখের পরে দুখ
চিরে শান্তির বুক
সে তো বৃক্ষ মূক
যে করে হতাশার ভিক্ষা
বিস্মৃত কী হওনি তুমি
শয্যায় বসে দুঃখের ভূমি
সুখ তো দুখের কর্ম পরীক্ষা
আচারে তোমার শান্তির আহারে
দুঃখ তো তুল্য তুল্য ঝরে
ফল পেয়ে হাতে
চিন্তা কেন আঁতে
হারিয়ে গিয়ে বুদ্ধিশক্তি
ভুলে যাও প্রাণভক্তি
সহ্য সীমা পার
আসবে বার বার
কী আছে অধিকার
হত্যা নিজেকে তোমার
সে কী তোমার
ভাব মনে বার বার
চলো আবার হও উত্থিত
ভয়কে করে ভীত
শরীর মনের উজ্জল গগনে
ছেরে হতাশার মৃত ভবনে
ওঠ জ্বলে বজ্রের ন্যায়
করে দুঃখকে জয়
যেওনা বেঁচেও মরে
দেখবে স্বর্ণসুখ পরবে ঝরে ঝরে

Recovery img for gionee m2: CTR, TWRP,PHILZ RECOVERY in one place

hello all device have a stock recovery .but
it is not suitable for good work like custom    custom ROM install, zip flash etc.
so you need a custom recovery.
your phone must be need root.
if your device is not rooted click here.
after root now you do the following thing:
download "mobile uncle tool.apk"
you can download "mobile uncle tool" from here(click here ).
after download  move the file to sdcard (not inside any folder)
now download this zip  for gionee m2 only(try another device brick your device). and extract it then you see recovery.img
now move it to sdcard .
then install mobile uncle tool and open.
now it will prop root permission .you will grant it.
now you will see "recovery update".
click that .then you will see recovery img  with ". img" .
click the recovery img. then it will alert  like"are you sure to flash".then you click yes. then wait some time .then another alert will be showed like "are you reboot to recovery" .you click yes.then it will reboot into recovery. after going recovery you will see a "reboot" button .click this .then you see three button. then you click "system".
then your phone will switch on.that's all.
you are successfully installed twrp recovery.
after that you can go to recovery following this type:
switch off your phone .
then click volume up button (+ve) and hold.
then click power on button and hold both button until the display is lighted.
then remove your fingers from button.
now you will goto recovery.
You can use other recovery:
1:ctr recovery (not need extract)
2: phillz recovery(need extract)

#*please comment*#

How to root your android phone

Root is such thing by which you can do anything with your device.
But root can brick your device ,so do it at own risk.
but I told that by root you can do anything such as
You can install custom ROM, flash zip and customize in your own .after root your warranty will be void
If you want to  root download this app from here here
then install and open. Then just click"try it"and  wait until 100% .don't click anything during root.then a popup will appear such as you are successfuly root.
That's all.
*warn*