  Herbig Ae/Be stars are intermediate-mass pre-main sequence stars undergoing
accretion through their circumstellar disk. The optical and infrared (IR)
spectra of HAeBe stars show HI emission lines belonging to Balmer, Paschen and
Brackett series. We use the archival X-Shooter spectra available for 109 HAeBe
stars from Vioque et al. (2018) and analyse the various HI lines present in
them. We segregated the stars into different classes based on the presence of
higher-order lines in different HI series. We discuss the dependence of the
appearance of higher-order lines on the stellar parameters. We find that most
massive and younger stars show all the higher-order lines in emission. The
stars showing only lower-order lines have Teff < 12000 K and an age range of
5-10 Myr. We perform a Case B line ratio analysis for a sub-sample of stars
showing most of the HI lines in emission. We note that all but four stars
belonging to the sub-sample show lower HI line ratios than theoretical values,
owing to the emitting medium being optically thick. The HI line flux ratios do
not depend on the star's spectral type. Further, from the line ratios of
lower-order lines and Paschen higher-order lines, we note that line ratios of
most HAeBe stars match with electron density value in the range 10^9 - 10^11
cm^-3. The electron temperature, however, could not be ascertained with
confidence using the line ratios studied in this work.
