[en] Cross-sections for the reactions ⁸⁵Rb(α,2n)⁸⁷Y, ⁸⁵Rb(α,3n)⁸⁶Y and ⁸⁵Rb(α,αn)⁸⁴Rb have been determined in the α-energy range of 20-50 MeV. Integral recoil ranges of the evaporation residue for the reaction ⁸⁵Rb(α,αn)⁸⁴Rb have also been measured. From the recoil range data, the linear momentum transfer to the product nucleus for the above reaction has been deduced. The experimental results are compared with theoretical model predictions. For (α,xn) reactions, the agreement between the theory and the experiment is found to be quite satisfactory. In case of (α,αn) reaction, the theoretical calculations fail to reproduce the experimental cross-sections as well as linear momentum transfer even when the incident α-energy is quite low. (orig.)