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Radioactive decay follows first-order kinetics. The initial amount of two radioactive elements X and Y is 1 gm each. What will be the ratio of X and Y after two days if their half-lives are 12 hours and 16 hours respectively?
Concept: First Order Reactions
A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is reduced to half?
Concept: Factors Influencing Rate of a Reaction
Which metal in the first transition series (3d series) exhibits + 1 oxidation state most frequently and why?
Concept: General Properties of the Transition Elements (D-block)
Which of the following cations are coloured in aqueous solutions and why ?
Sc3+, V3+, Ti4+, Mn2+ (At. Nos. Sc = 21, V = 23, Ti = 22, Mn = 25)
Concept: General Properties of the Transition Elements (D-block)
How would you account for the following?
Transition metals exhibit variable oxidation states.
Concept: General Properties of the Transition Elements (D-block)
Complete the following chemical equations:
`(i) Cr_2O_7^(2-)+6Fe^(2+)+14H^+ ->`
`(ii) 2CrO_4^(2-)+2H^+ ->`
`(iii) 2MnO_4^-+5C_2O_4^(2-)+16H^+ ->`
Concept: General Properties of the Transition Elements (D-block)
Complete the following equations:
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
Complete the following equations: Cr2O72- + 14H+ + 6I →
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Write the element which shows maximum number of oxidation states. Give reason.
Concept: General Properties of the Transition Elements (D-block)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element has the highest m.p?
Concept: General Properties of the Transition Elements (D-block)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element shows only +3 oxidation state?
Concept: General Properties of the Transition Elements (D-block)
The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co
Answer the following: Which element is a strong oxidising agent in +3 oxidation state and why?
Concept: General Properties of the Transition Elements (D-block)
Why do the transition elements have higher enthalpies of atomisation?
Concept: General Properties of the Transition Elements (D-block)
In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?
Concept: General Properties of the Transition Elements (D-block)
Complete the following equation:
\[\ce{2MnO4- + 6H+ + 5NO2- ->}\]
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
What are the consequences of lanthanoid contraction?
Concept: F-block Elements >> The Lanthanoids
Write the formula of an oxo-anion of Chromium (Cr) in which it shows the oxidation state equal to its group number
Concept: General Properties of the Transition Elements (D-block)
Account for the following:
Zn, Cd and Hg are soft metals.
Concept: F-block Elements >> The Lanthanoids
Following are the transition metal ions of 3d series:
Ti4+, V2+, Mn3+, Cr3+
(Atomic numbers: Ti = 22, V = 23, Mn = 25, Cr = 24)
Answer the following:
1) Which ion is most stable in an aqueous solution and why?
2) Which ion is a strong oxidising agent and why?
3) Which ion is colourless and why?
Concept: General Properties of the Transition Elements (D-block)
Complete the following equations:
`2MnO_4^(-)+16H^++5S^(2-)rarr`
Concept: Some Important Compounds of Transition Elements - Oxides and Oxoanions of Metals
