سومرہ چہ لرے لرے کیگی جنان
دومرہ مے زڑہ تا نزدے کیگی جنان
ووایا سنگہ با خوبونہ وکڑی
چہ دا چا سترگو کے اوسیگی جنان
قسمتہ دغہ سزہ پاتے وہ لا
چہ دا رقیب سرہ خندیگی جنان
زما نادان زرگیہ صبر وکڑہ
لا دا غرور پہ ٹال زنگیگی جنان
لکہ باران شیبے شیبے آتلہ
داسے مے زڑہ باندے واریگی جنان
Friday, 23 October 2015
Atal
Glacial Acetic Acid
Glacial acetic acid is the undiluted form of acetic acid. It doesn’t contain any water; thus, it has 100% acetic acid only. Glacial acetic acid is diluted by adding water to prepare the required concentration of acetic acid solutions. Since it is too concentrated, the acidity of glacial acetic acid is high. Therefore, it is corrosive and can damage the skin if in contact.
Glacial acetic acid is a trivial name for water-free (anhydrous) acetic acid. Acetic acid is an organic compound with the chemical formula CH3COOH. It is a colourless liquid that when undiluted is also called glacial acetic acid. Although it is classified as a weak acid, acetic acid is highly dangerous to skin. A common abbreviation for acetic acid is HOAc, where Ac stands for the acetyl group CH3−C(=O)−.
HO--Ac or HO-(O=)C-CH3 or
CH3-C(=O)-OH or CH3COOH
Friday, 16 October 2015
Rubai Tabasum Marwat
دومرہ چہ خوگ باد سحر راغے
خکاری دا لوری دا دلبر راغے
دا زڑہ دنیا تا مے دا خدائ دا لوری
دا پاکے مینے پیغامبر راغے
نن پہ جامو کے نہ زائیگمہ زہ
ستا دا راتللو چہ خبر راغے
خلقہ ور پاسئ تبسم مروت دے
دا تورو سترگو سوداگر راغے
L E
THE LEVELLING EFFECT, LEVELLING AND DIFFERENTIATING SOLVENTS
The apparent strength of a protonic acid is dependent on the solvent in which the acid is dissolved. When all the acids in the acid chart which are stronger than H3O+ ion
(i.e., the acids above H3O+ acids) are added to H2O, they donate as proton to H2O to H3O+ ion and appear to have equal strength, since all these acids are levelled to the strength of H3O+ ion which is left in solution and is common to all such solutions.
This phenomenon viz. The strength of all the acids becomes equal to that of H3O+ion is called leveling effect of the solvent, water, and here water is called a leveling solvent for all these acids.
In aqueous solution all very strong bases like Na+H–, Na+NH2–, Na+OC2H5– are levelled to the strength of OH– ion, for they react completely with H2O to produce OH–ions.
The solvent in which complete proton-transfer occurs are called levelling solvents.
In other words, the solvent in which the solute is ~100% ionised, are called levelling solvents.
Since HF and HCl both are ~ 100% ionised in liquid NH3 to give ~100% NH4+ ions, these appear to be of equal strength and liq. NH3 acts as a levelling solvent for HF and HCl. In H2O, HF is only partially ionised, whereas HCl and HBr are ~ 100% ionised.
Thus H2O is a differentiating solvent for HF, but for HCl and HBr it is a leveling solvent. Several mineral acids are partially ionised in glacial CH3COOH medium because CH3COOH is a poor proton-acceptor but rather a better proton donor.
CH3COOH, therefore, acts as a differentiating solvent towards the mineral acids. But, for bases, CH3COOH act as a leveling solvent.
The weaker the acid, the stronger the conjugate base.
It is very hard to discriminate between strong acids in water since they are fully deprotonated, so a mol of HI and a mol of HBr each act like one mol of H3O+. A solvent which is a weaker proton acceptor is needed to tell the difference.
The same logic applies to strong bases, one mole of any strong base can be treated as one mole of hydroxyl ions.
This is called the leveling effect - the limitation by the solvent of how strong acids or bases can be.
If two weak acids are put into a solvent which is a strong proton acceptor, such as ammonia, it is likewise hard to tell the difference between the two acids, since they will both act like a mol of ammonium ions. So the leveling effect changes with the solvent.
Solvent leveling
HI (l) + H2O(l) = H3O+(aq) + I-(aq)
HBr (l) + H2O(l) = H3O+(aq) + Br-(aq) Because HI(l) and HBr(l) are strong acids, both transfer their protons essentially completely to give H3O+. In effect, solutions of HI and HBr behave as though they are solutions of H3O+ regardless HI is intrinsincally stronger than HBr. Water is therefore said to have a leveling effect that brings all strong acids down to the acidity of H3O+. To distinguish the acidity strengths of HBr and HI, one has to use a less basic solvent. Similar situation exists for strong bases. In water, strong bases behave as solutions of OH-. The strengths of strong bases can only be distinguished using a less acidic solvent.
Leveling Effect, which states that the strongest acid that can exist in aqueous solution is H3O+.
Thursday, 1 October 2015
Leveling effect
Differently strong acids behave identically strong in solvents where the conjugate acid formed is weaker than the said acids. This effect is called LE or solvent effect.
eg HCl and HNO3 show equal strength in their aqueous solutions. It is because either when added to water forms H3O+ ions- a conjugate acid. Both HCl and HNO3 are stronger than H3O+. So both are 100% converted to H3O+. So in the solution they both become H3O+ and lose their identity or identical strength. In other words, they are levelled by the solvent. So in aqueous solution we can't say which one is stronger.
HCl+H2O= H3O+ +Cl-
1 99 99
HNO3 +H2O = H3O+ + NO3
1 99 99
On the other hand, if we compare CH3COOH, a weaker acod then H3O+, withe HCl or HNO3, the former will be weaker. Because being weaker than H3O, it doesn't dissolve completely.
CH3COOH+H2O = H3O+ + CH3COO-
99 1 1
The same is the case for strong bases
Their strength too becomes indistinguishable in solutions where they form conjugate bases weaker than them.