Sharepoint CSOM Write to website's properties

// Starting with ClientContext, the constructor requires a URL to the 
// server running SharePoint. 
ClientContext context = new ClientContext("http://SiteUrl"); 

// The SharePoint web at the URL.
Web web = context.Web; 

web.Title = "New Title"; 
web.Description = "New Description"; 

// Note that the web.Update() does not trigger a request to the server
// because the client library until ExecuteQuery() is called. 
web.Update(); 

// Execute the query to server.
context.ExecuteQuery();