,X and Y are respectively
1. X = , Y =
2. X = , Y =
3. X = , Y =
4. X = , X =
When iron becomes passive by "X", it is due to the formation of "Y". X and Y, respectively, are:
1. Dil. HCl,
2. 80% Conc. ,
3. Conc. ,
4. Conc. HCl,
When 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.
Which of the following statements is false?
1. | MnO2 dissolves in conc. HCl, but does not form Mn4+ ions. |
2. | oxidizes hot concentrated liberating oxygen. |
3. | is formed when infused KOH is oxidized by air, , or |
4. | The decomposition of acidic is not catalyzed by sunlight. |
Pick out the incorrect statement:
1. is quite strongly oxidizing and stable only in very strong alkalies. In dilute alkali, neutral solutions, it disproportionates.
2. In acidic solutions, is reduced to and thus, is widely used as an oxidizing agent.
3. does not act as an oxidizing agent in alkaline medium
4. is manufactured by the fusion by pyrolusite with KOH in the presence of air or , followed by electrolytic oxidation in alkaline solution.
The aqueous solution of is green because it contains
1. green ions
2. green
3. blue ions and green ions
4. blue ions and yellow ions
Colorless solutions of the following four salts are placed separately in four different test tubes and a strip of copper is dipped in each one of these. Which solution will turn blue?
1.
2.
3.
4.
The addition of non-metals like B and C to the interstitial sites of a transition metal increases
1. Ductility
2. Melting Point
3. Shining
4. Conductivity
The incorrect statement about transition elements is:
1. The most stable oxidation state is +3 and its stability increases across the period.
2. Transition elements of 3d-series atomic sizes increase from Cr to Cu.
3. Examples of alloys of transition metals with non-transition metals are brass (copper-zinc) and bronze (copper-tin).
4. Some transition elements like Ni, Fe, and Cr may show zero oxidation state in some of their compounds.
Which of the following metals does not form amalgam?
1. Fe
2. Au
3. Zn
4. Ag
The incorrect statement is
1. an acidified solution of liberates iodine from Ki
2. is used as a standard solution for estimation of ions
3. in acidic medium, M = N/6 for
4.
The catalytic activity of transition elements is not related to
1. Variable oxidation states
2. surface area
3. Complex formation ability
4. Magnetic moment
Anhydrous ferric chloride is prepared by:
1. Heating hydrated ferric chloride at a high temperature in a stream of air
2. Heating metallic iron in a stream of dry chlorine gas
3. The reaction of ferric oxide with HCI
4. The reaction of metallic iron with HCI
Knowing that the chemistry of lanthanoids (Ln) is dominated by its + 3 oxidation state, which of the following statements is incorrect
1. Because of the large size of the Ln (III) ions, the bonding in its compounds is predominantly ionic in character
2. The ionic sizes of Ln (III) the decrease in general with increasing atomic number
3. Ln (III) compounds are generally colorless
4. Ln (III) hydroxides are mainly basic in character
Which of the following ions is the most stable in aqueous solution
1.
2.
3.
4.
The actinodis exhibits moe number of oxidation states is greater than the lanthanoids. This is because
1. The 5f orbitals are more buried than the 4f orbitals
2. There is a similarity between 4f and 5f orbitals in their angular part of the wave function
3. The actinoids are more reactive than the lanthanoids
4. The 5f orbitals extend further from the nucleus than the 4f orbitals
The element of the first transition series having lowest oxidation potential value is -
1. Mn
2. Fe
3. Ni
4. Cu
In the first transition series, the highest b.p. and m.p. is of
1. Cr
2. V
3. Ni
4. Fe
In the following d block elements, the lowest melting point and boiling point are exhibited by
1. Cr
2. Hg
3. Cu
4. Au
The incorrect statement among the following about the chemistry of 3d and 4f series elements is
1. | 3d elements show more oxidation states than 4f series elements. |
2. | The energy difference between 3d and 4s orbitals is very little. |
3. | Europium (ll) is more stable than Ce (ll). |
4. | The paramagnetic character of the 3d series elements increases from scandium to copper. |
Which of the following elements has the strongest metallic bond?
1. | Fe | 2. | Sc |
3. | V | 4. | Cr |
The correct order of density is
1. Cu > Ni > Zn > Sc
2. Ni > Cu > Zn > Sc
3. Zn > Cu > Ni > SC
4. Sc > Zn > Ni > Cu
The ionization potential values of d-block elements as compared to the ionization potential values of f-block elements are:
1. | Higher | 2. | Equal |
3. | Lower | 4. | Can't compare. |
The incorrect statement among the following regarding Cerium is -
1. | The +4 oxidation state of cerium is not known in solutions. |
2. | The +3 oxidation state of cerium is more stable than the +4 oxidation state. |
3. | The common oxidation states of cerium are +3, and +4. |
4. | Cerium (IV) acts as an oxidizing agent. |
The native silver metal forms a water-soluble complex with a dilute aqueous solution of NaCN in the presence of :
1. Nitrogen
2. Oxygen
3. Carbon dioxide
4. Argon