Explanation
A eutectic mixture is defined as a mixture of two or more components which usually do not interact to form a new chemical compound but, which at certain ratios, inhibit the crystallization process of one another resulting in a system having a lower melting point than either of the components.
One mole of CaCl2 is more effective in melting ice than one mole of NaCl is explained by the Van’t Hoff factor. Van’t Hoff factor (i) for CaCl2 is 3 and that of NaCl is 2. Hence the freezing point depression is greater for CaCl2 than NaCl. Eutectic mixture of CaCl2/H2O freezes at -55° C while that of NaCl/ H2O freezes at -18° C. And Calcium chloride produces an exothermic reaction when mixed with water or when placed on top of ice, which means that it literally heats up when it comes in contact with ice. Sodium chloride does not produce this exothermic reaction.
Calcium sulphate is used as plaster of Paris as (CaSO4)2.H2O. Plaster of Paris is used to support broken bones during the healing process. When a broken limb is set in a cast made of a paste of plaster of Paris in water, movement of the bone is restricted, which helps the bone to heal. Calcium sulphate is also used as gypsum (CaSO4.2H2O) in the cement industry. Calcium sulphate is a salt.
Glauber’s salt is Na2SO2.10H2O.
Within a period, the size decreases from left to right, i.e. Na > Mg > Li > Be.
The ratio of their charge to size i.e. polarizing power is nearly the same.
The hydroxides of Ist group are strong bases and HCl is a strong acid, therefore, the chlorides of Ist group elements are salts of strong acids and strong bases. As such they do not undergo hydrolysis thereby yielding neutral solutions.
Alkali metals are highly electropositive and thus highly reducing. There is no other stronger reducing agent than those of alkali metals. Therefore, reduction, double decomposition and displacement methods for their extraction are not suitable. Only electrolytic methods are useful for their extraction.
H+ ions are discharged at a higher potential when Hg cathode is used than that using Pt cathode.
On dissolving moderate amount of Na metal in liquid NH3, the solution is blue in colour and paramagnetic but not diamagnetic.
As the size of the anion increases from F- to I-, the covalent character increases and hence the solubility in non-polar solvent increases:
LiI > LiBr > LiCl > LiF.
LiCl being covalent has the lowest melting point. The melting points of other halides decrease form NaCl to CsCl as the lattice energies decrease.
The hole in cryptand-222 is just of the right size for k+ ion to fit in whereas Na+ and Li+ are too small and Rb+ too big to fit in the hole. Thus, K+ ion forms the most stable cryptate 222.
Because KO2 not only provides oxygen but also removes CO2 both of which are important life supporting processes.
4KO2 + 2CO2 → 2K2CO3 + 3CO2
4KO2 + 4CO2 + 2H2O → KHCO3 + 3CO2
Li2O and Li3N
Please disable the adBlock and continue. Thank you.
