"Round the clock"

Anonymous wrote:

Is it right to use the phrase "around the clock " in place of  "round the clock" ?Would it mean the same?

To me, you have this backward. The question is, is round the clock, clearly ungrammatical, valid in lieu of around the clock.

Also,is the phrase "24/7" unprofessional ? can it be used in  formal english?

The simple answer is no. The more complex answer depends on what you consider formal English as the context for this.

Anonymous wrote:

Is it right to use the phrase "around the clock " in place of  "round the clock" ?Would it mean the same?

Yes.

Idioms, Oxford, new edition, page 59 gives

around/round the clock

(example has it even this way round-the-clock)

Anonymous wrote:

Also,is the phrase "24/7" unprofessional ? can it be used in  formal english?

24/7 (24-7) is considered slang, but is used normally in a formal way to describe a type of service.

source Wikipedia:

24/7 is an abbreviation which stands for "24 hours a day, 7 days a week".

In commerce and industry, it identifies a service that will be present regardless of current time or day, as might be offered by a supermarket, ATM, gas station, diner or restaurant, concierge services or manned datacenter.

24/7 can also refer to:

• a type of BDSM play, see 24/7 (BDSM).
• 24/7, a fictional supermarket/convenience store chain in the fictional state of San Andreas, in the video game Grand Theft Auto: San Andreas.
• a game mode for ESPN NBA 2K5, where a basketball player is created and played as if the player is playing in real life.