Solubility products of Al(OH)3 and Zn(OH)2 are 8.5 × 10-23 and 1.8 × 10-4 respectively. If both Al3+ and Zn2+ ions are present in a solution, which one will be precipitated first on addition of NH4OH?
Al(OH)3
Zn(OH)2
Both (a) and (b)
None of these
In a reversible isothermal process, the change in internal energy is
zero
positive
negative
None of these
Based on the following thermochemical equations
H2O (g) + C(s) → CO (g) + H2 (g); H = 131 kJ
CO (g) + O2(g) → CO2 (g); H = -282 kJ
H2 (g) + O2 (g) → H2O (g); H =-242 kJ
C (s) + O2 (g) → CO2 (g); H = X kJ
the value of X will be
-393 kJ
-655 kJ
+393 kJ
+655 kJ
The first ionisation potential of Na, Mg, Al and Si are in the order
Na < Mg > Al < Si
Na > Mg > Al > Si
Na < Mg < Al > Si
Na > Mg > Al < Si
Elements of which group form anions most readily?
Oxygen group
Nitrogen group
Halogens
Alkali metals
The weakest acid among the following is
CH3COOH
CH2ClCOOH
CHCl2COOH
CCl3COOH
A.
CH3COOH
Presence of electron withdrawing group (like Cl, NO2 etc) alongwith -COOH group increases the acidity of carboxylic acid by stabilising carboxylate ion. Since, in CH3COOH, no electron withdrawing group is present, thus it is the weakest acid among the given.