The Ecclesall representative was chosen for the leader of the opposition role by elected party members this week after Coun Colin Ross stood down.
Coun Mohammed was Coun Ross’s predecessor as leader, until he lost his council seat at the elections in 2014.
The Lib Dems took two seats from Labour in this month’s city council elections. Coun Mohammed also stood against new Brightside and Hillsborough MP Gill Furniss in the by-election held after the death of Harry Harpham.
For more on the significance of those gains from Labour in the council elections, see The Dangers of Premature Stakhanovite Optimism (aka Liberal Democrat Newswire #80).