Identify the incorrect statement from the following
- Alkali metals react with water to form their hydroxides
- The oxidation number of K in KO2 is +4.
- Ionisation enthalpy of alkali metals decreases from top to bottom in the group.
- Lithium is the strongest reducing agent among the alkali metals.
The Correct Option is B
Solution and Explanation
To determine the incorrect statement, let's analyze each option:
Alkali metals react with water to form their hydroxides: This statement is correct. Alkali metals react vigorously with water, giving hydrogen gas and forming their respective hydroxides.
The oxidation number of K in KO2 is +4.: This statement is incorrect. In potassium superoxide (KO2), potassium (K) actually has an oxidation state of +1. The oxygen molecule in KO2 is in the form of a superoxide ion (O2-), which has an oxidation state of -1/2 per oxygen atom. The potassium ion balances the charge, resulting in potassium's oxidation state remaining +1.
Ionisation enthalpy of alkali metals decreases from top to bottom in the group: This is correct. As we move down the group in the periodic table, the atomic size increases, and the outermost electron is farther from the nucleus, requiring less energy to remove, thus ionisation enthalpy decreases.
Lithium is the strongest reducing agent among the alkali metals: This statement is correct. Lithium has the highest tendency to lose its outer electron compared to other alkali metals, making it a very strong reducing agent. This is due to its high hydration energy.
Therefore, the incorrect statement is: The oxidation number of K in KO2 is +4.
Top Questions on p -Block Elements
Given below are two statements.
In the light of the above statements, choose the correct answer from the options given below:- JEE Main - 2025
- Chemistry
- p -Block Elements
Given below are two statements:
Statement I: Nitrogen forms oxides with +1 to +5 oxidation states due to the formation of $\mathrm{p} \pi-\mathrm{p} \pi$ bond with oxygen.
Statement II: Nitrogen does not form halides with +5 oxidation state due to the absence of d-orbital in it.
In the light of the above statements, choose the correct answer from the options given below:- JEE Main - 2025
- Chemistry
- p -Block Elements
Given below are the pairs of group 13 elements showing their relation in terms of atomic radius. $(\mathrm{B}<\mathrm{Al}),(\mathrm{Al}<\mathrm{Ga}),(\mathrm{Ga}<\mathrm{In})$ and $(\mathrm{In}<\mathrm{Tl})$ Identify the elements present in the incorrect pair and in that pair find out the element (X) that has higher ionic radius $\left(\mathrm{M}^{3+}\right)$ than the other one. The atomic number of the element (X) is
- JEE Main - 2025
- Chemistry
- p -Block Elements
- Thionyl chloride on reaction with white phosphorus gives a compound of phosphorus 'C' which on hydrolysis gives an oxo acid 'O'. The correct statements about C and O are
I. Shape of 'C' is pyramidal
II. 'O' is a dibasic acid
III. 'O' is a monobasic acid
IV. 'C' on reaction with acetic acid gives 'O'- TS EAMCET - 2025
- Chemistry
- p -Block Elements
- Which one of the following statements is not correct?
- TS EAMCET - 2025
- Chemistry
- p -Block Elements
Questions Asked in NEET exam
- With the help of the given pedigree, find out the probability for the birth of a child having no disease and being a carrier (has the disease mutation in one allele of the gene) in the F3 generation.
- NEET (UG) - 2025
- Genetics
- The plates of a parallel plate capacitor are separated by d. Two slabs of different dielectric constant \(K_1\) and \(K_2\) with thickness \(d/2\) and \(d/2\) respectively are inserted in the capacitor. Due to this, the capacitance becomes two times larger than when there is nothing between the plates. If \(K_1 = 1.25 K_2\), the value of \(K_2\) is :
- NEET (UG) - 2025
- Capacitors and Capacitance
- The correct order of the wavelength of light absorbed by the following complexes is:
A. $[ \text{Co(NH}_3\text{)}_6]^{3+}$
B. $[ \text{Co(CN)}_6]^{3-}$
C. $[ \text{Cu(H}_2\text{O)}_4]^{2+}$
D. $[ \text{Ti(H}_2\text{O)}_6]^{3+}$
Choose the correct answer from the options given below:- NEET (UG) - 2025
- Coordination chemistry
- Consider the diameter of a spherical object being measured with the help of a Vernier Callipers. Suppose its 10 Vernier Scale Divisions (V.S.D.) are equal to its 9 Main Scale Divisions (M.S.D.). The least count in the M.S. is 0.1 cm and the zero of V.S. is at -0.1 cm when the jaws of Vernier callipers are closed. If the main scale reading for the diameter is \(M = 5\) cm and the number of coinciding vernier division is 8, the measured diameter after zero error correction, is:
- NEET (UG) - 2025
- Measurement of length
- In some appropriate units, time (t) and position (x) relation of a moving particle is given by \(t = \alpha x^2 + \beta x\). The acceleration of the particle is :
- NEET (UG) - 2025
- Kinematic equations for uniformly accelerated motion
Concepts Used:
P-Block Elements
- P block elements are those in which the last electron enters any of the three p-orbitals of their respective shells. Since a p-subshell has three degenerate p-orbitals each of which can accommodate two electrons, therefore in all there are six groups of p-block elements.
- P block elements are shiny and usually a good conductor of electricity and heat as they have a tendency to lose an electron. You will find some amazing properties of elements in a P-block element like gallium. It’s a metal that can melt in the palm of your hand. Silicon is also one of the most important metalloids of the p-block group as it is an important component of glass.
P block elements consist of:
- Group 13 Elements: Boron family
- Group 14 Elements: Carbon family
- Group 15 Elements: Nitrogen family
- Group 16 Elements: Oxygen family
- Group 17 Elements: Fluorine family
- Group 18 Elements: Neon family