= Solution
In the regime where salt promotes <chromatin> condensation by screening repulsion between DNA-rich surfaces, reducing salt from 0.15 M to 0.1 M weakens the effective attraction. In the schematic upper-critical model this means a lower critical temperature and a smaller coexistence region; at a fixed suitable temperature the dilute-phase <saturation concentration> rises. The second curve is therefore drawn inside and below the first. The magnitude of the shift is not specified by the question.
This direction has a microscopic basis: reducing ionic strength increases the range of electrostatic repulsion between negatively charged <DNA> segments. Modelling of interacting arrays supports a role for screening and <nucleosome> contacts in stabilizing chromatin-rich phases.<Nucleosome plasticity is a critical element of chromatin liquid-liquid phase separation and multivalent nucleosome interactions by Stephen E. Farr and others>[Salt-dependent coexistence and the role of nucleosome breathing]{ref}
In the idealized limit of unscreened DNA-DNA repulsion, the ordinary condensed phase can disappear, rather than simply acquiring an arbitrarily small positive critical temperature. However, \b[zero added NaCl is not literally zero counterions]: charged <chromatin> requires charge compensation, and buffer ions and counterions associated with the preparation remain. Salt also screens attractive interactions, and very high salt can alter <nucleosome> stability. The proposed shift applies to the stated low-salt screening regime, not a universal monotonic law at every salt <concentration>.
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