Dear Authors,

I received an additional review of the revised version of your manuscript, attached below. In general, the reviewer is in favor of publication of this work. However, the reviewer has a few minor comments, I would like to ask you to address before proceeding with the publication of this manuscript.

With kindest regards,

Daniel Knopf

Review:
The manuscript describes the evaporation rates of water from ice in presence of HCl. Two distinct, complex types of evaporation behavior are described and the difference is assigned to an ice – HCl/water binary system and to an amorphous HCl/water system. The findings and conclusions somewhat extend the previous studies from this group. The description of results is detailed and the conclusions are well supported in the discussion. I therefore suggest publication as additionally the topic is well suited for ACP as well as being one of the major questions in HCl-ice-atmosphere context.

I still feel that the introduction does not prepare the reader well enough for the results and discussion. On the one hand, the topic of acid dissociation is which covers more than a page of the manuscript is not at all taken up in the discussion. Even worse, taken that the atmospheric implications (5) discuss the lifetime of cloud particles this seems to be the central science tackled by the research. The introduction does not even once mention lifetime (except when giving goals of this paper) – I think you need to explain to the reader why this is important and which aspects are open concerning lifetime of ice particles in the atmosphere. In summary, the open questions around the water flux are still not clearly presented in the introduction, or lost in the details of the text, and the new aspects of this work relative to the previous publications could be more emphasized. However, I leave this decision to the editor.

Comments:
L 161 ff: “The question has to be raised whether the two types of used ice films may be responsible some of the discrepancies in the results because both the density and the structure of ice are known to be a strong function of temperature and deposition conditions (Kuhs et al., 2012; Schriver-Mazzuoli et al., 2000).
This line gives the discussion of HCl dissociation a good reason with relevance to this work. I wonder, though, why the question of dissociation is not picked up in the discussion again taken that it occupies a rather large part of the introduction.
L 199 ff: “It appears that two observed HCl species on/in ice, namely single phase amorphous HCl/H2O mixtures and a binary phase consisting of pure ice and an as yet unidentified crystalline HCl hydrate, HCl•xH2O, decrease Jev(H2O) to a different extent as proposed in Delval et al. (2003).”
Appear to me very close to the conclusions a, b, and e. May I ask you to stress the new findings in slight more detail.
L 288: The average mole fraction χHCl of HCl in the remaining ice film as a function of time is calculated according to Delval and Rossi (2005).
Please detail on the method. Is this a direct measure of HCl deposited to the sample or rather indirect based on the gas-phase signal (dosage).
Figure 2. Why are experiments 5 and 6 not discussed. Would this be a third type of ice?
Figure 2. Why is experiment 10 not shown even thought it is discussed in the text? Please add.

Dear Authors,

I am happy to accept your manuscript as article for publication in Atmospheric Chemistry and Physics.

With kindest regards,

Daniel Knopf