Question

In which of the following pairings of compounds are both members of the pair strong
electrolytes?

NaCN and LiI

NH3 and HI

NaOH and H2CO3

KBr and HBr

more than one answer is correct

Answer 1

1) NaCN and LiI are strong electrolytes (100% dissociated) as they dissociate into and ions in case of NaCN (as NaCN is a salt) and and in case of LiI (LiI is also a salt) and conduct electricity

2) is a weak electrolyte because when it is dissolved in water it, ionises partially i.e less than 100% dissociated and HI is a strong electrolyte as it dissociates (100%) into and ions respectively when dissolved in water

4) KBr is a salt and ionises into and ions in water and HBr is also a strong electrolyte as it dissocites into and ions respectively in water

3) NaOH is a salt and thus ionises 100% and is a strong electrolyte where as is once again a weak electrolyte as ionises less than 100%, a similar case which is explained with respect to ammonia above.

So, pairs in option 1 and option 4 are strong electrolytes

HBr and HI are strong electrolytes because the Br and I atoms are comparitively bigger (when compared with F and Cl) and the shared electrons are not strongly attracted by their nuclei and thus the covalent bond is easily broken as in H-Br and H-I

Atomic size generally increases from top to bottom in a group due to the addition of extra shell...

All salts are strong electrolytes as they dissciate into ions 100% when dissolved in water

So, the answer is option 5 (more than one answer is correct)