This chapter belongs to a previous NCERT/CBSE curriculum and is not part of the current 2026-27 chapter list. Removed in 2022-23.
Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter The p-Block Elements. This page offers a step-by-step solution to the specific question from Exercise 1, Question 1:
Why are pentahalides more covalent than trihalides?
. With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.Why are pentahalides more covalent than trihalides?
The group 15 elements (nitrogen, phosphorus,arsenic,antimony and bismuth) when reacted with halogen atom ,tend to form halides. The halides formed are of two types:
1) Trihalides (MX3)
2) Pentahalides (MX5) where M -15TH group element X- halogen atom
The trihalides are formed by all the elements of group 15 while pentahalides are formed by all the elements except nitrogen because there is absence of vacant d- orbital in its outermost shell.
The oxidation state of +5 in pentahalides is more as compared to +3 oxidation state in trihalides. Due to the higher positive oxidation state of central atom in pentahalide state, these atoms will have larger polarizing power than the halogen atom attached to them. The central atom in pentahalide state will tend to polarize more the halide ion to which it is attached.
But In case of trihalides due to +3 oxidation state the central atom will polarize the halogen atom to a lesser extent as compared to pentahalide state. Therefore, more the polarization, larger will be the covalent character of the bond.
Hence due larger polarization of bond in pentahalide state as compared to trihalide state, the pentahalides are more covalent than trihalides.
The reaction between A and B is first order with respect to A and zero order with respect to B. Fill in the blanks in the following table:
| Experiment |
A/ mol L - 1 |
B/ mol L - 1 |
Initial rate/mol L - 1 min - 1 |
| I | 0.1 | 0.1 |
2.0 × 10 - 2 |
| II | -- | 0.2 |
4.0 × 10 - 2 |
| III | 0.4 | 0.4 | -- |
| IV | -- | 0.2 |
2.0 × 10 - 2 |
NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:
Stay updated with our latest educational content and study tips
It’s not about starting over if you took a break to care for children, take care of yourself, be healthy or for any other reason. This is a realistic strategy for the recovery of skills, selection of the right job, and overcoming the resume problem. One year, three years or 10 years of a career … Read more
Read MoreThere’s no need to score 95% or achieve a JEE/NEET rank. You don’t need to score 95% or rank in JEE/NEET to build a solid career. A candid and pragmatic guide to the routes that actually work for students who have an average mark and what to do when faced with the options. If … Read more
Read MoreAI tools, online platforms that are much cheaper than coaching centres and the changing idea of what “structure” even means have upended this argument more in the past two years than in the decade preceding it. Here’s what is really the case for 2026 – and what has actually stayed the same. If you look … Read more
Read MoreStarting to make a new career after 30 isn’t a start from scratch. Marketing, teaching, financial, retail, healthcare, sales and other professionals can pursue careers in technology by applying the existing knowledge and skills they have acquired to new technology skills. There are various ways to enter the technology industry, such as in IT support, … Read more
Read MoreCalculate percentage from obtained marks and total marks.
Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 1: Why are pentahalides more covalent than trihalides?....
Fresh educational articles and updates.
Most-read articles from SaralStudy.
Fast access to frequently used study resources.
Recently viewed articles based on SaralStudy activity.
Comments
More the polarization more the covalent. I couldn't understand this line. If there is more polarization it could be more ionic. Am i correct.please clarify me
Supb
Great one.
Nice ... no words
Thank a lot
Thank a lot
your answer gives exact knowledge which not found anywhere .great work!
Really great thanks alot! It clear my alot of doubts
THANK YOU!!!
Best answers ever than other books.