Principles Related to Practical Chemistry
- Match List I with List IIList I (Ion): A. Co^2+ B. Mg^2+ C. Pb^2+ D. Al^3+List II (Group Number in Cation Analysis): I. Group-I II. Group-III III. Group-IV IV. Group-VIChoose the correct answer from the options given below : Answer: 2. A-III, B-IV, C-I, D-II Key idea: recall the group of each cation in qualitative analysis. mathrmPb²⁺ : Group I (precipitated as c... 1
- During the preparation of Mohr's salt solution (Ferrous ammonium sulphate), which of the following acid is added to prevent hydrolysis of Fe^2+ ion? Answer: 1. dilute sulphuric acid Key idea: mathrmFe²⁺ salts hydrolyse in water, so a little acid is added, and it must not oxidise mathrmFe²... 1
- Given below are certain cations. Using inorganic qualitative analysis, arrange them in increasing group number from 0 to VI.A. Al^3+ B. Cu^2+ C. Ba^2+ D. Co^2+ E. Mg^2+Choose the correct answer from the options given below: Answer: 2. B, A, D, C, E Key idea: group numbers in qualitative analysis. mathrmCu²⁺ : Group II ( H₂S in acid). mathrmAl³⁺ : Group III ( NH₄... 1
- Pumice stone is an example of - Answer: 4. solid sol Key idea: Name a colloid by its dispersed phase and dispersion medium. Pumice stone is a solid that traps gas, so gas i... 1
- Given below are two statements :Statement I :In the coagulation of a negative sol, the flocculating power of the three given ions is in the order -Al^3+ > Ba^2+ > Na^+Statement II :In the coagulation of a positive sol, the flocculating power of the t… Answer: 4. Statement I is correct but Statement II is incorrect. Key idea: by the Hardy-Schulze rule, the coagulating ion is the one with ch... 1
- Measuring Zeta potential is useful in determining which property of colloidal solution ? Answer: 3. Stability of the colloidal particles Zeta potential is the potential difference between the fixed layer of charge on a colloidal... 1
- Which mixture of the solutions will lead to the formation of negatively charged colloidal [AgI]I^- sol. ? Answer: 1. 50 mL of 1 M AgNO ₃ + 50 mL of 1.5 M KI or 2. 50 mL of 1 M AgNO ₃ + 50 mL of 2 M KI In the sol [AgI]I^- , AgI adsorbs the common... 1
- On which of the following properties does the coagulating power of an ion depend ? Answer: 2. Both magnitude and sign of the charge on the ion According to the Hardy-Schulze rule, the ion that coagulates a colloid is the on... 1
- The coagulation values in millimoles per litre of the electrolytes used for the coagulation of As_2S_3 are given below:I. (NaCl) = 52, II. (BaCl_2) = 0.69,III. (MgSO_4) = 0.22The correct order of their coagulating power is Answer: 2. III > II > I Key idea: coagulating power is inversely proportional to coagulation value (the minimum amount needed). Smaller valu... 1
- Fog is a colloidal solution of : Answer: 1. Liquid in gas Key idea: fog consists of tiny water droplets (liquid) dispersed in air (gas), so it is a colloid of liquid in gas,... 1
- Which one of the following characteristics is associated with adsorption ? Answer: 2. Δ G , Δ H and Δ S all are negative Key idea: adsorption is spontaneous, exothermic and reduces the freedom of the adsorbate. Spon... 1