I want to make a chart in which I am able to show bars which will start from 'start time' and end on the 'end time' (in the image, time is from 4:32 pm to 6:24 pm but bar does not show the same). I want the columns = 24 hr time and rows i want the date

Ah I see. That's because the date pill is using HOUR. That will truncate the minutes and seconds. Try creating this calc:

Hour Numeric

// Tranlate the hour of the start time to a decimal number.
// Minutes and seconds will be a portion of an hour.
DATEPART('hour', [Start Time])+
DATEPART('minute', [Start Time])/60+
DATEPART('second', [Start Time])/3600

Then use that on the columns shelf. Make sure the pill is a dimension and that it is continuous.

See attached.