Test Preparation on IIT JEE Mains Mock Test-10
CHEMISTRY
pH of water is 7 when a solute X is dissolved in water, the pH of the solution becomes 12 The solute X is a salt of
Since the solution becomes basic on addition of solute X , so the solute is a salt of weak acid and strong base.
On adding dilute hydrochloric acid to an aqueous solution of a salt and warming, a colourless gas with pungent odour is evolved along with the formation of a yellow ppt. this indicates the presence of ..........in the salt.
On reaction with dilute HCl, the salt containing sulphide (S2-) or sulphite (SO3-) ions liberate H2S and SO2 gases respectively; sulphate ions do not give any reaction. Thiosulphate (S2O32-) gives SO2 gas which has a pungent odour and yellow ppt of colloidal sulphur.
S2O32- + 2H+ → SO2↑ + S↓ + H2O
Hydrogen peroxide is used as
Hydrogen peroxide acts as both oxidising and reducing agent.H2O2 → H2O + O : H2O2 + O → H2O + O2
Equal quantities of electricity are passed through three voltameters containing FeSO4, Fe2(SO4)3 and Fe (NO3)3. Consider the following statements in this regard.
Fe2+ requires 2F for conversion to Fe; Fe3+ requires 3F so if equal quantities of electricity are passed the amount of iron deposited from Fe(NO3)3 is 2/3 of that deposited from FeSO4.
Which of the following reactions depict the oxidizing behaviour of H2SO4?
In the reaction, 2HI + H2SO4 → I2 + SO2 + 2H2O; iodine changes its oxidation state from -1 (in HI) to 0 (oxidation), i.e., H2SO4 oxidizes HI to I2.
Which of the following halides is not oxidized by MnO2?
F- is not oxidized by MnO2.
The activation energy for a simple chemical reaction A B is Ea in forward direction. The activation energy for the reverse reaction
If the reverse reaction is endothermic, heat liberated is less but if it is exothermic more heat is liberated as compared to the forward reaction. Thus the activation energy for the reverse reaction can be can be less than or more than Ea.
In the reaction, I2 +2S2O32– 2I– + S4O62– equivalent mass of iodine is
In the reaction I2 → 2I-, the change is of 2 electrons; I2 + 2e → 2I-, therefore, the equivalent mass of I2 is ½ of its molecular mass.
An aqueous solution contains the following ions: Hg22+, Hg2+, Pb2+ and Cd2+. The addition of dil. HCl (6N) precipitates
On addition of dilute HCl, cations Hg22+ and Pb2+ are precipitated as chlorides Hg2Cl2 and PbCl2. The cations Hg2+ and Cd2+ are not precipitated as chlorides in 1st group of salt analysis.
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