Solubility of which among the following solids in water changes slightly with temperature?
KNO3
NaNO3
KBr
NaBr
In the ln K vs plot of a chemical process having S° > 0 and H° < 0, the slope is proportional to (where K is equilibrium constant).
-|H°|
|H°|
S°
-S°
For the process,
A → B, at 298 K, G° is 163 kJ mol-1. The composition of the reaction mixture is [B] = 1 and [A] = 10000. Predict the direction of the reaction and the relation between reaction quotient (Q) and the equilibrium constant (K).
Forwards direction because Q > K
Reverse direction because Q > K
Forward direction because Q < K
Reverse direction because Q < K
Water gas is produced by
Passing steam over red hot coke
Passing steam and air over red hot.
Burning coke is excess air.
Burning coke is limited supply of air.
The correct descending order of the heat liberated (in kJ) during the neutralisation of the, acids CH3COOH (W), HF (X), HCOOH (Y) and HCN (Z) under identical conditions (Ka of CH3COOH = 1.8 × 10-5, HCOOH =1.8 × 10-10 HCN = 4.9 × 10-10 and HF = 3.2 × 10-4)
Y > X > Z > W
X > Y > W > Z
W > X > Y > Z
Z > W > Y > X
How many times a 0.1 M strong monobasic acid solution should be diluted so that pH of the resulting solution is tripled?
50
10
25
100
D.
100
Since, pH = -log[concentration]
Therefore, for change in one unit of pH, concentration must be changed to 10 times.
pH = -log (10-1)
= log 10 = 1
If pH = 3, then
3 = -log 10-x
3 = x log 10
x = 3
Thus, for change in concentration to get 3 times of pH, the solution must be diluted to 100 times.
The equilibrium pressure for the given reaction, is /4 atm at 400 K. The Kp for the given reaction (in atm2) is
MSO4.2H2O (s) MSO4 (s) + 2H2O (g)