The reaction(s) involved in the preparation of potassium dichromate from iron chromite ore is/are:
1. | FeCr2O4 + NaOH + O2 → Na2CrO4 + Fe2O3 + H2O |
2. | Na2CrO4 + H2SO4 (conc.) → Na2Cr2O7 + Na2SO4 + H2O |
3. | Na2Cr2O7 + KCl→ K2Cr2O7 + NaCl |
4. | All of the above. |
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyThe fusion of chromite ore (FeCr2O4) with Na2CO3 in air gives a yellow solution upon the addition of water. Subsequent treatment with H2SO4 produces an orange solution.
The yellow and orange colours, respectively, are due to the formation of:
1. Na2CrO4 and Na2Cr2O7
2. Cr(OH)3 and Na2Cr2O7
3. Cr2(CO3)3 and Fe2(SO4)3
4. Cr(OH)3 and Na2CrO4
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyWhen neutral or faintly alkaline is treated with potassium iodide, the iodide ion is converted into 'X'. The formula of 'X' is:
1.
2.
3.
4.
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyHCl is not used to make the medium acidic in oxidation reaction of , because
1. | Both HCl and KMnO4 act as oxidising agents. |
2. | KMnO4 oxidises HCl into Cl2, which is also an oxidising agent. |
3. | KMnO4 is a weaker oxidising agent than HCl. |
4. | KMnO 4 acts as a reducing agent in the presence of HCl. |
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyA gas that can readily decolorize an acidified KMnO4 solution is:
1.
2.
3.
4.
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyCrO42- (yellow) changes to Cr2O72- (orange) in pH = x and vice versa in pH = y.
The value of x and y will be:
1. 6, and 8
2. 6, and 5
3. 8, and 6
4. 7, and 7
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyWhich of the following pairs of substances on reaction will not evolve gas?
1. Iron, and (aq)
2. Iron, and steam
3. Copper, and HCl(g)
4. Sodium, and ethyl alcohol
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyThe oxidation state of chromium in the final product formed by the reaction between KI and acidified potassium dichromate solution will be:
1. +2
2. +3
3. +4
4. +6
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyHighest oxidation state of manganese in fluoride is +4 (Mn) but the highest oxidation state in oxides is +7 (Mn2O7). The reason is :
1. | Fluorine is more electronegative than oxygen. |
2. | Fluorine does not possess d orbitals. |
3. | Fluorine stabilizes lower oxidation state of Mn. |
4. | In covalent compounds, fluorine can only form a single bond while oxygen forms a double bond. |
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & BiologyWhen KMnO4 solution is added to hot oxalic acid solution, the decolorization is slow in the beginning but becomes instantaneous after some time. This is because :
1. acts as auto catalyst.
2. is formed.
3. Reaction is exothermic.
4. catalyses the reaction.
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NEET MCQ Books for XIth & XIIth Physics, Chemistry & Biology